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Ibn A˓bbad

ZEINA MATAR

Abū al-Qāsim Ismā ī˓l Ibn ˓Abbād Ibn al-˓Abbās Ibn˓Abbād Ibn Ahmad Ibn Idrīs, also known as Kāfial-Kufāt, and al-S.āh. ib, was a famous vizier and man ofletters of the Buwayhid period. There is disagreementabout his place and date of birth, but he was probablyborn at Is.t.akhr on 16 Dhū’l-qa d˓a 326/14 September938. His family included high dignitaries, and his ownfather had been a kātib (clerk) and then vizier, or ministerof state, under the Buwayhid Prince Rukn al-Dawla(r. 35/946–366/976).

Ibn ˓Abbād himself became the disciple and secretaryof Abū’l-Fad. l Ibn al-˓Amīd (d. 360/970), the father ofthe Buwayhid vizier Abū’l-Fath. Ibn al-˓Amīd (b. 337/948–9). His close relationship to the Buwayhid amīrs(princes) is said to have begun in 347/958, when heaccompanied Mu’ayyid al-Dawla (reigned 366/976–373/983) to Baghdad as a clerk. He was later confirmedin this office when Mu’ayyid al-Dawla became gover-nor of Isfahan. Ibn ˓Abbād’s career took a more sig-nificant turn when he was appointed vizier, replacingAbū’l-Fath. Ibn al-˓Amīd.

Ibn ˓Abbād served two rulers: Mu’ayyid al-Dawlaand Fakhr al-Dawla (reigned 373/983–387/997). Themain source for the study of his vizierate remains thevolumeof theRasā i˒l ( A˓zzam1946),which is a collectionof administrative pieces, appointment, and other officialletters by Ibn A˓bbād. According to the sources, thepersonality of Fakhr al-Dawla was not really compatiblewith that of Ibn A˓bbād, although he recognizedthe latter’s administrative skills and talents. When IbnA˓bbād died on 24 Safar 385/30 March 995, Fakhr al-Dawla confiscated his property, and from that timeonward, no other member of his family was to beappointed to a high official position.

Ibn ˓Abbād was not only a statesman and a politician,but he was also a talented writer whose works cover avery wide spectrum. In their article in the Encyclopediaof Islam, Claude Cahen and Charles Pellat give a

classification of his works: dogmatic theology, history,grammar and lexicography, literary criticism, poetry,and belles-lettres.In Abū H. ayyān al-Tawh. īdī’s Mathālib al-Wazīrayn,

a comprehensive list of Ibn ˓Abbād’s works is given.Some of the most important are:

. Kitāb al-Muh. īt. bi- l˓-lugha (The ComprehensiveTreatise About Language) in 10 vols

. Kitāb Dīwān rasā’ilihi (Collection of Letters) in10 vols

. Kitāb al-Kāfī. Rasā i˒l (The Book of al-Kafī [thatwhich is sufficient]. Letters [or Correspondence])

. Kitāb al-A y˓ād wa-fad.ā’il al-Nowrūz (The Book ofFeasts and the Excellent Qualities of New Year’sDay)

. Kitāb al-Wuzarā˒ (The Book of Viziers)

. Kitāb Dīwān Shi r˓(ihi) (Collection of Poetry)

In the Yatīmat al-dahr (III, 204), al-Tha ā˓libī commen-ted on a Risāla on medicine said to have been writtenby Ibn ˓Abbād:

I found that it combined beauty of style, eleganceof expression, and mastery of the subtleties andparticularities of medicine, and it showed that hewas thoroughly familiar with this science, and hada penetrating knowledge of its intricacies.

Ibn ˓Abbād often inspired very contradictory opinionsand feelings as is shown by Abū H. ayyān al-Tawh. īdī’shostility on the one hand, and by al-Tha ā˓libī’s praiseand admiration on the other. However, regardless ofpersonal like or dislike, he certainly was a highlyexceptional personality in Muslim history. Maybe onecan refer to him as a “patron-vizier”, a talented individualwho had the ability to mix politics and literature, and apoet whose court once counted as many as 23 poets.

References

Abū H. ayyān al-Tawh. īdī. Mathālib al-Wazīrayn. Ed. I. al-Kaylānī. Damascus: Dār al-Fikr, 1961.

Al-Tha ā˓libī. Yatīmat al-Dahr. Ed. M. Muh. iyyaddīn ˓Abādal-H. amīd. 4 vols. Mis.r: Dār al-Māmūn, 1956–1958.

˓Azzam, A. A. and S. D. ayf, ed. Rasā i˒l al-S.āh. ib Ibn A˓bbād.Cairo: Dār al-Fikr al˓Arabi, 1946.

1086 Ibn Al-˓Arabī

Cahen, C. Buwayhids. Encyclopaedia of Islam II. Vol. 1.Leiden: Brill, 1960. 1350–7.

Cahen, C. and C. Pellat. Ibn ˓Abbād. Encyclopaedia ofIslam II. Vol. 2. Leiden: Brill, 1971. 671–3.

Kahl, O. and Z. Matar. The Horoscope of as-S.āh. ib Ibn˓Abbād. Zeitschrift der Deutschen MorgenländischenGesellschaft 140.1 (1990): 28–31.

Matar, Z. and A. Vincent. A Little-Known Note (Ruq ā˒)Attributed to the Buyid Vizier al-S.āh. ib Ismā’īl Ibn ˓Abbād.Occasional Papers of the School of Abbasid Studies2 (1988): 46–56.

Yāqūt al-Rūmī. Mu j˓am al-Udabā .˒ Ed. A. F. Rifā ī˓. 20 vols.Mis.r: Dār al-Māmūn, 1936–1938.

Ibn Al- A˓rabı

WILLIAM C. CHITTICK

Muh.yī al-Dīn ibn al-˓Arabī is one of the mostinfluential Muslim thinkers of the past seven hundredyears. Born in Murcia in present-day Spain in 1165, heset out for the western lands of Islam in 1200, traveledin the Arab countries and Turkey, and, in 1223, settledin Damascus, where he lived until his death in 1240. Hewrote voluminously and attracted the attention ofscholars and kings during his own lifetime. Hismagnum opus, al-Futūh.āt al-makkiyya (The MeccanOpenings) – inspired sciences that were “opened” up tohis soul during his pilgrimage to Mecca – will fill some15,000 pages in its new edition. His most widelystudied work, Fus.ūs. al-h. ikam (The Bezels of Wisdom),is a short explication of the various modalities ofwisdom embodied by 28 of God’s prophets, fromAdam to Muhammad.

Ibn al-˓Arabī’s writings investigate every dimensionof Islamic learning, from the Qur ā˒n and the h. adīth(the sayings of Muh.ammad) to grammar, law, philoso-phy, psychology, andmetaphysics. His basic intellectualproject was to illustrate the unity of all human endeavorsand the underlying, interrelated functions of all humanthinking. He cannot be classified as a philosopher,theologian, scientist, or jurist, though his works addressmost of the basic epistemological issues of these dis-ciplines. He saw himself as an inheritor of the wisdomof the prophets, but one who was given the duty ofexplaining this wisdom in the subtlest intellectualdiscourse of the day – at a period that is looked backupon as the high point of Islamic learning. He providesno system, but rather a unified vision that is capableof spinning off innumerable systems, each of themappropriate to a given field of learning or level ofunderstanding. He offers many ways of approaching thebasic questions of human existence, such as the nature ofreality itself, the role of God, the structure of the cosmosand the human psyche, the goal of human life, and

the relationship of minerals, plants, and animals toother creatures. In short, he provides basic patterns forestablishing complex systems of metaphysics, theology,cosmology, psychology, and ethics.

Ibn al-˓Arabī was followed by a number of majorthinkers who systematized his “openings” in variousways, depending upon their own orientations andintellectual contexts. The diverse interpretations givento his works are especially obvious in a series of over100 commentaries that have been written on his Bezelsof Wisdom from the thirteenth century down to moderntimes. His stepson S.adr al-Dīn Qūnawī (d. 1274) hadprobably the keenest philosophical mind among Ibnal-˓Arabī’s followers. Qūnawī in turn trained manydisciples, several of whom wrote widely influentialworks. Sa ī˓d al-Dīn Farghānī (d. 1296) provided sys-tematic expositions of the teachings of both Qūnawīand Ibn al-˓Arabī in Arabic and Persian. Fakhr al-DīnI˓rāqī (d. 1289) was a poet who wrote a delightfulsummary of Qūnawī’s teachings in mixed Persianprose and poetry that helped popularize Ibn al-˓Arabī’steachings. Mu a˒yyid al-Dīn Jandī (d. ca. 1300) wrote inArabic the first detailed commentary on Ibn al-˓Arabī’sBezels of Wisdom. The intellectual tradition establishedby Ibn al-˓Arabī and Qūnawī gradually merged withvarious branches of Islamic philosophy, yielding a widerange of intellectual perspectives that dominated theIslamic wisdom tradition down to the coming ofWestern colonialism.

In order to grasp Ibn al-˓Arabī’s importance for thehistory of scientific thought in Islam, one needs tounderstand his basic accomplishment, which was toestablish an honored place in the Islamic intellectualtradition for supra-rational knowledge. From theirinception in the eighth and ninth centuries, the mainlineschools of theology and philosophy in Islam hadendeavored to understand the Quranic revelation on thebasis of rational modes of investigation taken over fromthe Greek heritage. Parallel to this, there developed amore practical, existential approach that found the goalof human life in direct experience of the presence ofGod. This second approach, which came to be called bythe umbrella term “Sufism,” laid stress upon supra-rational modes of knowledge that are collectivelyknown as kashf (unveiling), i.e., the lifting of the veilsthat separate the human soul from God. Unlike someSufis, Ibn al-˓Arabī was not opposed to acknowledgingthe authority of reason. However, he maintained thatunveiling was a higher form of knowledge, because itgrows out of the unmediated perception of God’sactuality. In Ibn al-˓Arabī’s way of looking at things,reason tends innately to divide and discern. It eliminatesconnections between God and the cosmos and under-stands God as distant and transcendent. In contrast,unveiling works by seeing sameness and presence;hence God is perceived as near and immanent. Perfect

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Ibn Al-A l˓am 1087

knowledge of God and of reality as a whole dependsupon a happy balance of reason and unveiling. Onlythrough this balance can God be perceived in appropri-ate modes as both absent and present, near and far,transcendent and immanent, wrathful and merciful. Ibnal-˓Arabī’s works are devoted largely to explaining thevast range of these appropriate modes.

The long term effect of the marriage between reasonand unveiling effectuated by Ibn al-˓Arabī is symbo-lized by his meeting when still a boy – of perhaps 15years – with the philosopher Ibn Rushd (Averroesd. 1198). Ibn al-˓Arabī had already experienced theopening of the unseen worlds, and Ibn Rushd, whowas a friend of his father, had asked to meet him. In thebrief exchange that took place, Ibn Rushd asked ifunveiling and reason achieved the same goals. Ibnal-˓Arabī replied, “Yes and no.” Then, in crypticlanguage, he affirmed that reason was a valid routeto achieve knowledge of the nature of things, but hedenied that it exhausted the possibilities of humanknowing. In the West, the teachings of Ibn Rushd wereemployed to help establish nature as an autonomousrealm of intellectual endeavor. Under the discerningeye of reason, God was abstracted from perceivedreality, eventually becoming a hypothesis that could bedispensed with. The world of nature was now theproper site for rational analysis and dissection, andthe result has been the ever-increasing fragmentationof human knowledge, with a total divorce betweenscience and ethics. In contrast, Ibn Rushd was forgottenin the Islamic world, but Ibn al-˓Arabī and his followerssucceeded in establishing a harmony between reasonand unveiling. Hence Muslim intellectuals were neverable to conceive of nature as a realm cut off fromGod. If God is present in all things, then the ethical andmoral strictures that he establishes through revela-tion need to be observed at every level. It becomesimpossible to investigate the natural world without atthe same time investigating its relationship with Godand recognizing the moral and ethical demands thatthis relationship entails.

Ibn al-˓Arabī’s career and teachings exemplify thedimensions of Islamic learning. The worldview towhich he gave detailed expression provided a perspec-tive from within which Muslim intellectuals were ableto answer the deepest questions of the human mind. Ibnal-˓Arabī’s achievements contributed to an intellectualequilibrium that refused to subordinate the spiritualdemands of human beings to corporeal demands andthat gradually established a vast framework withinthe context of which the intellectual disciplines cameto be ever more united and interrelated. This holisticperspective on knowledge in turn prevented the frag-mentation of the Islamic worldview and allowed noroom for “declarations of independence” by specificschools of science or philosophy. Given that ethics,

morality, and spiritual development lay at the heartof this perspective, it was impossible to divorce anybranch of science or learning from these concerns.

References

Addas, Claude. Quest for the Red Sulphur: The Life of IbnA˓rabī. Cambridge: The Islamic Texts Society, 1993.

Bashier, Salman H. Ibn al- A˓rabī’s Barzakh: The Concept ofthe Limit and the Relationship Between God and theWorld. Albany: State University of New York Press, 2004.

Chittick, William C. The Sufi Path of Knowledge: Ibnal- A˓rabī’s Metaphysics of Imagination. Albany: StateUniversity of New York Press, 1989.

---. The Self-Disclosure of God: Principles of Ibn al- A˓rabī’sCosmology. Albany: State University of New York Press,1998.

---. Science of the Cosmos, Science of the Soul: ThePertinence of Islamic Cosmology in the Modern World.Oxford: Oneworld, 2006.

Chodkiewicz, Michel. An Ocean Without Shore: Ibn A˓rabī,The Book, and the Law. Albany: State University of NewYork Press, 1993.

Corbin, Henry. Creative Imagination in the Sūfism of IbnA˓rabī. Princeton: Princeton University Press, 1969.

Hirtenstein, S. and M. Tiernan eds. Muhyiddin Ibn A˓rabī: ACommemorative Volume. Shaftesbury: Element, 1993.

▶www.ibnarabisociety.org.

Ibn Al-A l˓am

RAYMOND MERCIER

Ibn al-A l˓am, Abū’l-Qasim ˓Alī ibn I˓sa al-Husain,al-˓Alawī, al-Sharīf was a tenth century astronomer,apparently established in Baghdad. The year of hisdeath is recorded by Ibn al-Qift.ī as 375/985. The Zīj(astronomical handbook with tables) which he wrote islost, but substantial information about it may begleaned from notices in the work of other astronomers.His work was patronized by the Būyid ruler ˓Ad.ūdal-Dawla but suffered from lack of support in thedisturbed period which followed his death in 372/982.A near contemporary, the great astronomer IbnYūnus

of Cairo, reports that Ibn al-A l˓am had fixed the lengthof the year as 365; 45, 40, 20 days, determined theposition of Regulus (α Leonis) in the year 365/975–6 as15; 6 Leo, and also fixed the rate of precession, onedegree in 70 Persian years. He remarks that Ibn al-A l˓amwas known everywhere for the exactitude of his obser-vations and the extent of his geometrical knowledge.Al-Bīrūnī in his work Tamhīd al-mustaqarr li-tah. qīq

ma n˓ā al-mamarr (On Transits) gives the name of hisZīj as al- A˓dūdī, and incidentally provides values forthe radius of the epicycles for each of the planets.

1088 Ibn al-Bannā˒

In spite of the loss of the Zīj full information about itsparameters may be obtained from two sources compiledin the fourteenth century, the Persian Zīj-i Ashrafī, andan anonymous Arabic collection known as the Dastūral-Munajjimīn. Information is also available fromGreek sources, in which Ibn al-A l˓am is referred to asAlim (‘Aλημ). The Greek manuscripts are of thefourteenth and fifteenth centuries, but they preservetexts older than the Persian and Arabic compilations.These include scholia to the Almagest datable to AD1032 which refer to tables composed for the Greekcalendar from the work of Ibn al-A l˓am, as well as twohoroscopes for the years AD 1153 and AD 1162 whichhave been calculated from such tables, apparently forthe Emperor Manuel Comnenus. The tabulation of theequations indicates that the technique of “displace-ments” was used in order to provide values of theequations which were always positive.

See also: ▶Zij, ▶Ibn Yūnus

References

Kennedy, E. S. Al-Bīrūnī on Transits. Beirut: AmericanUniversity of Beirut, 1959.

Mercier, Raymond. The Parameters the Zīj of Ibn al-A l˓am.Archives Internationales d’Histoire des Sciences 39(1989): 22–50.

Tihon, Anne. Sur l’identité de l’astronome Alim. ArchivesInternationales d’Histoire des Sciences 39 (1989): 3–21.

Ibn al-Banna˒

EMILIA CALVO

Ibn al-Bannā˒ al-Marrākushī, Abū-i- a˓bbās Ah.mad ibnMuh.ammad ibn ˓Uthmān al-Azdī was born in Marra-kesh, Morocco on 29 December 1256 and died,probably in Marrakesh, in 1321. He studied the Arabiclanguage, grammar, the Qu r˒ān, H. adīth (commentariesof the prophet), and also mathematics, astronomy, andmedicine; but his fame is due to his knowledge ofmathematics. His teachers in this field were Muh. -ammad ibn Yah.yā al-Sharīf, Abū Bakr al-Qallūsī, andAbū ˓Abd Allah ibn Makhlūf al-Sijilmāsī. He alsostudied medicine with al-Mirrīkh.

Among his disciples were al-Lajā˒ī, teacher of IbnQunfūdh, Muh.ammad ibn Ibrah. im al-Abūlī, Abū-l-Barakāt al-Balāfiqī, and Ibn al-Najjār al-Tilimsānī.

He is credited with having written more than 80works. Among them are an introduction to Euclid, atreatise on areas, an algebra text, a Kitāb al-anwā˒(about asterisms and stars used in meteorology andnavigation), an almanac, two abridgements of treatises

by Ibn al-Zarqāllu on the use of the s.afīh. as (astrolabes)zarqāliyya and shakkāziyya entitled, respectively, Risālatal-s.afīh. a al-mushtaraka a˓lā al-shakkāziyya (Epistle onthe Shakkāziyya Plate), in 23 chapters, and Taqbīl a˓lārisālat al-s.afīh. a al-zarqāliyya (Epistle on al-Zarqālī’sPlate). However, his two most important works are theMinhāj and the T. alkhīs. .

The Kitāb minhāj al-t.ālib li ta d˓īl al-kawākib (TheWay of Him Who Seeks the Equation of the Planets)is a very practical book for calculating astronomicalephemerides. This zīj (astronomical handbook withtables) is based on the one by Ibn Ish.āq. The twoof them are highly dependent on Ibn al-Zarqāllu’sastronomical theories.

The Talkhīs. a˓māl al-h. isāb (Summary of Arithmeti-cal Operations) was widely diffused in the Arabicworld because of its conciseness, which makes it easyto memorize. Al-Qalas.ādī, among others, wrote animportant commentary on it. A different version of thiswork, more extensive and complete, has been editedrecently by Saidan (1984) under the title Al-maqālāt fīi˓lm al-h. isāb li-Ibn al-Bannā˒ (The Treatises on theScience of Computation by Ibn al-Bannā˒). Theprocedures found in the Talkhīs. are studied here in amore detailed way.

See also: ▶Ibn al-Zarqāllu, ▶Ibn Qunfūdh

References

Al-Fāsī, M. Ibn al-Bannā˒al- a˓dadī al-Marrākussī. Revista delInstituto Egipcio de Estudios Islámicos 6 (1958): 1–10.

Calvo, Emilia. La Risālat al-s.afīh.a al-mušraka a˓là al-šakkāziyya de Ibn al-Bannā˒ de Marrākuš. Al-Qant.ara 10(1989): 21–50.

Ibn al-Bannā .˒ Taljīs. a˓māl al-h. isāb. Edition and FrenchTranslation by Muhammad Souissi. Tunis: Université deTunis, 1964.

Puig, Roser. El Taqbīl valà risālat al-s.afīh.a alzarqāliyyade Ibn al-Bannā d˒e Marrākuš. Al-Qant.ara 8 (1987):45–64.

Renaud, H. P. J. Notes critiques d’histoire des sciences chezles musulmans. II. Ibn al-Bannā˒ de Marrakech, s.ūfī etmathématicien (XIII–XIVs. J.C.). Hespéris 25 (1938):13–42.

Saidan, A. S. Al-maqālāt fī i˓lm al-h. isāb li-Ibn al-Bannā .˒Ammān: Dār al-Furqān, 1984.

Samsó, Julio and Eduardo Millás. The Computation ofPlanetary Longitudes in the ‘Zij’ of Ibn al-Banna. ArabicSciences and Philosophy 8.2 (Sept. 1998): 259–86.

Sarton, George. Introduction to the History of Science.Vol. II.Baltimore: Williams & Wilkins, 1931. 998–1000.

Suter, H. and M. Ben Cheneb. Ibn al-Bannā .˒ Encyclopédie deI’Islam. 2nd ed. Vol. III. Leiden: E. J. Brill, 1971. 753–4.

Vernet, Juan. Contribución al estudio de la labor astronóm-ica de Ibn al-Bannā .˒ Tetuán: Editoria Marroquí, 1951.

---. Ibn al-Bannā˒ al-Marrākushī. Dictionary of ScientificBiography. Vol. I. New York: Charles Scribner’s Sons,1970. 437–8.

Ibn al-Hā˒im 1089

Ibn al-Bayt.ar

I

EMILIA CALVO

Ibn al-Bayt.ār al-Mālaqī, D. iyā˒ al-Dīn Abū Muh.ammad˓Abdallāh ibn Ah.mad, was a pharmacologist bornin Málaga, Spain at the end of the twelfth century(ca. AD 1190–1248). He studied in Seville with Abū-l-˓Abbās al-Nabātī, ˓Abdallāh ibn S.ālih. , and Abū-l-Hajjāj. He was interested in the works of al-Ghāfiqī,al-Zahrāwī, al-Idrīsī, Dioscorides, and Galen.

Around AD 1220 he migrated to the East and, in1224, arrived in Cairo where he was named chiefherbalist by the Ayyūbid Sultan al-Kāmil. He traveledthrough Arabia, Palestine, Syria, and Iraq. Ibn AbīUs.aybi a˓ was one of his followers and left a mention ofhis teacher full of praise in his ˓Uyūn.

Among Ibn al-Bayt.ār’s works we can mentionAl-Mughnī f ī’l-adwiya al-mufrada (The CompleteBook on Simple Drugs), dedicated to al-Kamil’s son,Sultan al-S.ālih. and dealing with the simple medi-cines, andAl-Jāmi˒li-mufradāt al-adwiyawa-l-aghdhiya(Compendium of Simple Drugs and Food), whichenumerates alphabetically some 1,400 animal, vegetable,and mineral medicines, as well as some 150 authoritiesincluding al-Rāzī and Ibn Sīnā.

Ibn al-Bayt.ār’s main contribution is the systematiza-tion of the discoveries made by the Arabs during theMiddle Ages in this field. He was also concerned withsynonymy, finding the technical equivalents betweenthe Arabic and Persian, Berber, Greek, Latin, andRomance languages. The Jāmi˒ had great influence inthe Near East, but less in the West. Andrea Alpago usedit in his works on Ibn Sīnā.

Other works of Ibn al-Bayt.ār, less known than theaforementioned two, are Mizān al-t.abīb (The Measureof the Physician), Risāla f ī’l-aghdhiya wa’l-adwiya(Treatise on Food and Medicines), Maqāla fī’l-laymūn(Treatise on the Lemon), and Tafsīr kitāb Diyusqūrīdis(Explanation of Dioscorides’ Book) in which heinventories 550 medicines found in the first four booksof Dioscorides.

References

Cabo González, Ana María. Ibn al-Baytar et ses apports à labotanique et à la pharmacologie dans le “Kitàb al-Gami”.Médiévales: Langue, Textes, Histoire 33 (1997): 23–39.

---. Las propiedades medicinales del acíbar según el ‘Kitabal-y de Ibn al-Baytar’. Revista de filologia de laUniversidad de La Laguna 17 (1999): 205–19.

Dubler, C. E. Ibn al-Bayt.ār en Armenio. Al-Andalus21 (1956): 125–30.

Ibn al-Baitar. On Medicinal Plants Systematics. HamdardMedicus 39.3 (July–Sept. 1996): 5–7.

Meyerhof, Max. Esquisse d’histoire de la pharmacologie etbotanique chez les musulmans d’Espagne. Al-Andalus3 (1935): 31–3.

Samsó, Julio. Las ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992.

Sarton, George. Introduction to the History of Science.Vol. II.Point 2. Baltimore: Williams & Wilkins, 1931.

Torres, M. P. Autores y plantas andalusíes en el Kitābal-Yāmi d˒e Ibn al-Bayt.ār. Actas del XII Congreso de laU.E.A.I. (Málaga, 1984). Madrid, Union européened’arabisants et d’islamisants, 1986. 697–712.

Vernet, Juan. Ibn al-Bayt.ār.Dictionary of Scientific Biography.Vol. I. New York: Charles Scribner’s Sons, 1970. 538–9.

---. Ibn al-Bayt.ār. Encyclopédie de I’Islam. 2nd ed. Vol. III.Leiden: E. J. Brill, 1971. 759–60.

Ibn al-Ha˒im

JULIO SAMSÓ

A˓bd al-H. aqq al-Ghāfiqī al-Ishbīlī is known as Ibnal-Hā i˒m. He was an Andalusian astronomer, probablyfrom Seville. He dedicated (ca. 1204) his very importantal-Zīj al-Kāmil fī’l-Ta ā˓līm (The Perfect Handbook onMathematical Astronomy) to the Almohad Caliph AbūA˓bd Allāh Muh.ammad al-Nās.ir (1199–1213). Thiswork, which is extant in a unique and incompletemanuscript in the Bodleian Library at Oxford University,was influential in the Maghreb and contributed to thedevelopment there of a new kind of astronomy in theAndalusian tradition. As a zīj (astronomical handbookwith tables), it is exceptional inWestern Islam, because itcontains a highly technical and complete exposition ofPtolemaic astronomy with geometrical demonstrations,and not a simple set of instructions for the use of thetables. It also conveys new information on the astronomi-cal works of the Toledan school of the eleventh century,the main representative of which was Ibn al-Zarqāllu/Azarquiel (d. 1100), as well as new planetary parameters.Ibn al-Hā i˒m appears as a defender of Zarqāllian ortho-doxy and harshly criticizes Ibn al-Kammād (fl. begin-ning of the twelfth century) for his modifications of Ibnal-Z. arqāllu’s doctrines. Ibn al-Hā i˒m’s zīj containednumerical tables (three have been preserved in the zīj ofIbn Ish.āq, who flourished in Tunis at the beginning ofthe thirteenth century) but an incomplete copy musthave circulated early for Ibn al-Raqqām (d. 1315) statesthat Ibn al-Hā i˒m did not include any tables in his work.

See also: ▶Ibn al-Zarqāllu, ▶Ibn al-Raqqām

References

Samsó, Julio. Las Ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992. 320–6.

1090 Ibn Al-Haytham (Alhazen)

Ibn Al-Haytham (Alhazen)

ROSHDI RASHED

Among the mathematicians of classical Islam, few areas famous as al-H. asan ibn al-H. asan ibn al-Haytham(Alhazen in the Latin West). A physicist and astrono-mer as well as mathematician, he quickly gained a widereputation, first in Arabic, in the Islamic East as well asthe Islamic West, and then from the translations of hisworks in optics and astronomy into Latin, Hebrew, andItalian.

But his renown, completely justified by the impor-tance of his contributions and especially of the scientificreforms accomplished in them, contrasts singularlywith the paucity of information we have on the man, histeachers, or his scientific milieu. Also, the significanceof his works surrounded the man with the aura of alegend. Sources available to us consist of narrativesrecounted by ancient bibliographers where legendbecomes mixed up with the rare historical evidence.These same narratives are precisely what modernbibliographers continue to reproduce partially or totallyuntil today. After a critical reading of these sources, verylittle information remains: born in Iraq, most likelyin Bassorah, sometime in the second half of the tenthcentury, Ibn al-Haytham arrived in Cairo, under thereign of Fat.imid al-H. ākim. He proposed a hydraulicproject to control the waters of the Nile, but it wasrejected by the Caliph. He continued to live in Cairountil his death, after 432/1040.

From the thirteenth century until today, biogra-phers have confused al-H. asan ibn al-Haytham withMuh.ammad ibn al-Haytham, a philosopher and theoristof medicine who lived in Baghdād at the same time.This confusion, due undoubtedly to similarity of thetwo names of these contemporary authors, is serious asit brings into question the authenticity of certainwritings attributed to al-H. asan ibn al-Haytham.

Biobibliographers, notably al-Qift.ī, cite 96 titles ofIbn al-Haytham, not all of which have survived. Half ofhis writings are in the field of mathematics, 14 onoptics, including the authoritative and voluminousKitāb al-Manāz. ir (Book of Optics), 23 on astronomy,two in philosophy (one on the Place and the other onthe Indivisible Part), three on statics and hydrostatics,two on astrology, and four on various other topics. Thisaccounting shows clearly that Ibn al-Haytham grappledwith all the mathematical sciences of that time, or atleast the most advanced part of this discipline. We willsee that he was always at the leading edge of researchor at the culmination of one tradition and the beginningof a new period. It is precisely this quality whichdistinguishes his contributions. Ibn al-Haytham lived

at a privileged time, his work following a century ofintense research in these fields by eminent scholarssuch as the Banū Mūsā, Thābit ibn Qurra and hisgrandson Ibrāhīm ibn Sinān, al-Qūhī, and Ibn Sahl, toname a few. We will now briefly examine the principalaspects of his research.

MathematicsIbn al-Haytham’s mathematical research was partic-ularly in the field of geometry and not of algebra.Ancient biobibliographers attributed a boo.k on algebrato him, but it has not survived. From the outset,geometers wanted to combine closely the study of thepositions of figures and their metric properties: in otherwords, to combine the geometry of Apollonius withthat of Archimedes. This combination is not a staticsynthesis, but a new organization of geometry whichpossessed a real heuristic value. Already initiated byal-H. asan ibn Mūsā and followed by Thābit, this workled to the study of geometric transformations andof projective methods. It was this work which Ibnal-Haytham developed further in his own geometricalstudies.

The contributions of Ibn al-Haytham in geometrycan be divided into several groups, the most importantof which are in infinitesimal mathematics and thetheory of conic sections and their applications. Hecomposed 12 treatises on infinitesimal mathematicsand then on conic theory. To those can be added a thirdarea in which Ibn al-Haytham takes up severalproblems relating to the foundations of mathematicsand their methods in his treatise Maqāla f ī’l-tah. līl wa‘l-tarkīb (On Analysis and Synthesis), his Kitāb f īal-ma ‘lūmāt (On the Known Things), his Sharh. Us.ūlUqlīdis f ī ‘l-handasa wa ‘l- a˓dad wa talkhīs.uhu(Commentary on the Elements of Euclid), and hisKitāb f ī H. all shukūk Kitāb Uqlīdis fi ‘l-us.ūl wa-sharh.ma ā˓nīh (Solutions to Doubts) again concerning Euclid.In these books, he deals as much with the constitutionof a new discipline, a kind of proto-topology, as withthe theory of the demonstration within the difficultiesraised by the fifth postulate of Euclid, or with the theoryof parallels. Ibn al-Haytham also edited an importantpaper on number theory, four treatises on arithmetic,and the same number on practical geometry.

Of the 12 papers on infinitesimal mathematics, onlyseven have survived. The first three are devoted to thestudy of lunes and the quadrature of a circle. Note thatthe calculation of the area of lunes involves thecalculation of sums or differences of areas of sectorsor of triangles, the comparison of which has recourse tothat of the ratio of angles or of the ratio of segments. Inthe most important of the three papers, Ibn al-Haythambegins by setting up four lemmas, the results of whichdemonstrate the role of the function f, defined as

Ibn Al-Haytham (Alhazen) 1091

I

f ðxÞ ¼ sin2xx

in the study of lunes.In his study Tarbī ˓al-dā i˒ra (On the Quadrature of a

Circle), he examines the relationship between provingthe existence of a magnitude or a property and thequestion of effectiveness of its construction.

Other treatises on infinitesimal mathematics dealwith the volume of a solid curve:Misāh. at al-mujassamal-mukāfi˒ (The Measurement of a Paraboloidal Solid)and Misāh. at al-kura (The Measurement of a Sphere).In calculating the volume of a paraboloid, Ibn al-Haytham deals rapidly with the volume of a revolvingparaboloid, which had already been studied by Thābitibn Qurra and al-Qūhī. He then moves on to his owninvention: how to calculate the volume of a paraboloidobtained from the rotation of a parabola around itsordinate. He shows that this volume is 8/15 of thevolume of the circumscribed cylinder. His calculationis equivalent to that of the integral

�

Z b

ak2ðb2 � 2b2y2 þ y4Þdy ¼ 8

15�k2b5 ¼ 8

15V ;

with V being the volume of the circumscribed cylinder.Ibn al-Haytham proceeded in this study with the help

of the method of integral sums, which he also applied incalculating the volume of a sphere. In order to do thiscalculation, Ibn al-Haytham generalized the proposi-tion X-1 of Euclid’s Elements. He devoted the seventhpaper in this group to that. This group includes animportant treatise devoted to isoperimetric and isepi-phane problems. It was the most advanced mathemati-cal work of its time and for several centuries following.In it, to study these extrema, he had to undertake thefirst substantial research on the theory of a solid angle.Moreover he combined both a projective method andan infinitesimal method.

Ibn al-Haytham’s second group of mathematicalwritings dealt with the theory of conic sections. He waswell acquainted with the Conics of Apollonius and hadcopied them in his own hand, so he knew that, in Greek,the eighth and last book was lost. He tried to reconstructthe book according to the indications of Apollonius. Inaddition to his writings on conics, he applied the theoryof the intersection of conics to the resolution of problemswhich cannot be constructed with a compass or ruler,problems either passed down (for example, the regularheptagon) or posed by him (for example, the solution ofa solid arithmetic problem). Ibn al-Haytham was oneof the first mathematicians who insisted on demonstrat-ing the existence of the point of intersection of two conicsin these last examples.

It is impossible in this space to explicate themathematical results of Ibn al-Haytham’s work. Butlet us simply note his expression of what is called

Wilson’s theorem, and the converse of Euclid’stheorem for perfect numbers.Indeed, in the course of solving the problem called

the Chinese Remainder, he stated Wilson’s theorem,which can be written as:n is prime

ðn� 1Þ!� 1ðmod nÞ:

As for the converse of Euclid’s theorem of perfectnumbers, he tried to show that any even perfectnumber is in Euclidean form, in other words in the form2p(2p + 1 – 1) with (2p + 1 – 1) prime.

OpticsA brief look at the work of Ibn al-Haytham on opticsreveals not only its revolutionary nature but also itscomprehensiveness, touching all the known branchesof optics: optics in its proper sense in his Book onOptics and his Discourse on Light; catoptrics, notablyburning mirrors (parabolic and spherical burningmirrors); dioptrics, in al-Kura al-muh. riqa (The Burn-ing Sphere); and meteorological optics in Daw a˒l-qamar (The Light of the Moon), Ad.wā˒ al-kawākib(The Light of the Stars), F ī s.ūrat al-kusūf (On theShape of the Eclipse) and al-Hāla wa-qaws quzah. (TheHalo and the Rainbow). With this extension, Ibn al-Haytham modified the meaning of optics. Optics is notany more reduced to a theory of direct vision, ageometry of the gaze with which a theory of vision isassociated, but also bears significantly on the theory oflight, its propagation, and its effects as a material agent.This leads us to the revolution accomplished by Ibnal-Haytham in optics and more generally in physics.Ibn al-Haytham sought to bring about a program

of reform, which led him to take up a whole range ofdifferent problems. The basic aspect of this reformwas toclarify the difference between the conditions of thepropagation of light and the conditions of the vision ofobjects. This led, on the one hand, to giving physicalsupport to the rules of propagation – making a firmmathematical analogy between a mechanical model ofthe movement of a solid ball thrown against an obstacleand that of light – and on the other hand to proceed-ing geometrically at all times, both by observation andby experimentation. Optics consisted henceforth oftwo parts: one, a theory of vision and the associatedphysiology of the eye and psychology of perception,and the other, the theory of light to which are linkedgeometric optics and physical optics. The organization ofthe Optics reflects this new situation: there are chaptersdevoted entirely to propagation, such as the third chapterof the first book and books IV to VII; others deal withvision and related problems. This reform also resulted inthe emergence of new problems, such as Alhazen’s

1092 Ibn Al-Haytham (Alhazen)

problem in catoptrics, the examination of the sphericallens and the spherical diopter, not only as burninginstruments but also as optical instruments in dioptrics,and to experimental control, viewed as much as a generalpractice of investigation as the norm of a proof in optics,and more generally in physics. Let us now take a quicklook at how this reform in optics was carried out.

Ibn al-Haytham rejected any doctrine of a raystemming out from the eye, called a visual ray, in orderto defend the intromissionist theory of visible forms.But unlike the intromissionists of antiquity, he did notbelieve that objects sent off “forms” or totalities whichemanated from the visible under the effect of light. Hesaw them rather as forms reducible to their elements:a ray emanating toward the eye from every point of avisible object. Looked at thus, the eye becomes a simpleoptical instrument. Ibn al-Haytham then explained howthe eye perceives the visible with the help of its raysemitted from all points. In the Optics he devotes the firstthree chapters to the foundations of this theory. In thethree following chapters, he deals with catoptrics. Theseventh and last chapter is devoted to dioptrics. Histheories rest on two qualitative laws of refraction and onseveral quantitative rules, all controlled experimentallywith the help of an instrument which he designed andbuilt himself. The two qualitative laws, known to hispredecessors Ptolemy and Ibn Sahl, can be stated asfollows:

1. The incident ray, the normal at the point ofrefraction, and the refracted ray are in the sameplane; the refracted ray gets closer (respectively, faraway) from the normal, if light passes from a milieuless (respectively, more) refringent to a milieu more(respectively, less) refringent

2. The principle of inverse return

Instead of pursuing the path opened up by hispredecessor Ibn Sahl, Ibn al-Haytham returned to astudy of angles in order to establish the quantitativerules. He devoted a substantial part of the seventh bookto a study of the refracted images of an object, notablyif the surface of separation of two milieux is eitherplanar or spheric. It was in the course of this study thathe fixed his attention on the spherical diopter and thespherical lens. He returned to the spherical lens in histreatise On the Burning Sphere, one of the high pointsof research in classical optics, in order to improve uponcertain results that he had already obtained in hisOptics. This treatise was the first deliberate study on thespherical aberration for parallel rays falling on a glasssphere and giving off two refractions.

AstronomyBy their number, their thematic variety, the power ofthe analysis they show, and by their results, the works

of Ibn al-Haytham in astronomy yield nothing to hiswor.ks in mathematics or optics. It should be noted onlythat an elementary treatise of Muh.ammad ibn al-Haytham, the Commentary on the Almagest is oftenerroneously attributed to Ibn al-Haytham. The attribu-tion of the book On the Configuration of the Universeto him is also doubtful. The authentic works ofIbn al-Haytham have not yet been seriously studied,a fortiori, apart from a few rare and particularcontributions, such as the Samt al- ibla bi-al-h. isāb(Determination of the Direction of Mecca by Cal-culation). It remained for subsequent astronomers,notably al-˓Urd. ī, one of the founders of the school ofMarāgha, to recognize their debt to Ibn al-Haytham’sbook al-Shukūk a˓lā Bat.lamyūs (Doubts on Ptolemy).Before assessing his contribution in astronomy, wemust wait until his books have received the editingand study that they deserve.

The impact of the work of Ibn al-Haytham variesaccording to the field. In mathematics, his influencecan be seen in the works of Ibn Hūd, al-Khayyām,Sharaf al-Dīn al-T. ūsī, and al-Samaw’al, among others.But we do not know anything of successors who mighthave tried to follow up on his research on lunes, thesolid angle, or the measurement of figures and solidcurves. In optics, the Latin translation of his Optics(under the title Perspectiva or De Aspectibus, reeditedin 1572 under the title Opticae Thesaurus) and histreatise On Parabolic Burning Mirrors provided abasis of research for centuries of scholars such asWitelo,Roger Bacon, J. Peccham, Frederick of Fribourg,Kepler, and Snell, among many others. In Arabic, thereis the commentary of Kamāl al-Dīn al-Fārsī. Finally inastronomy, there is the work of al-˓Urd. ī which showsthe influence of his work. It is too soon to measurethe impact of the writings of Ibn al-Haytham on hissuccessors in this field also, but they appear to beimmense.

See also: ▶Geometry, ▶Physics, ▶Optics, ▶al-Khayyām, ▶Sharaf al-Dīn al-T. ūsī, ▶Almagest

References

Hogendijk, Jan P. Two Editions of Ibn al-Haytham’sCompletion of the Conics. Historia Mathematica 29(2002): 247–65.

Michel, Alain. Géométrie et philosophie: De Thabit ibn Qurraà Ibn al-Haytham. Arabic Sciences and Philosophy 13(2003): 311–5.

Naz. īf, M. Al-H. asan ibn al-Haytham, buh.ūthuhu wa kush-ūfuhu al-bas.ariyya. 2 vols. Cairo: Nori Press, 1942–1943.

Rashed, R. Optique et mathématiques: recherches surl’histoire de la pensée scientifique en arabe. Aldershot:Variorum, 1992.

---. Géométrie et dioptrique au X e siècle: Ibn Sahl, al-Qūhī etIbn al-Haytham. Paris: Les Belles Lettres, 1993a.

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---. Mathématiques infinitésimales du IX e au XI e siècle. Vol.II. Ibn al-Haytham. London: al-Furqān Islamic HeritageFoundation, 1993b.

---. Analysis and Synthesis According to Ibn al-Haytham.Artifacts, Re.presentations and Social Practice. Ed.C. C. Gould and R. S. Cohen. Boston: Kluwer Academic,1994a. 121–40.

---. The Development of Arabic Mathematics: BetweenArithmetic and Algebra. Boston: Kluwer Academic,1994b.

Rashed, R. ed. Encyclopedia of the History of Arabic Science.3 vols. London: Routledge, 1996.

Rashed, Roshdi. Les mathématiques infinitésimales du IXe auXIe siècle [v. 4, Méthodes Géométriques, Transformationsponctuelles et Philosophie des Mathématiques, Ibnal-Haytham]. London: Al-Furqan Islamic HeritageFoundation, 2002.

Raynaud, Dominique. Ibn al-Haytham sur la vision binocu-laire: un précurseur de l’optique physiologique. ArabicSciences and Philosophy: A Historical Journal 13.1(2003): 79–99.

Sabra, A. I. The Optics of Ibn al-Haytham: Books 1–111 onDirect Vision. London: Warburg Institute, 1989.

Ibn al-Kammad

JULIO SAMSÓ

Abū Ja f˓ar Ahmad ibn Yūsuf ibn al-Kammād was anAndalusian astronomer who flourished in Cordobatoward the end of the eleventh century and the first halfof the twelfth. He was probably a direct disciple of Ibnal-Zarqāllu/Azarquiel (d. 1100) as well as the studentwho helped him in observations made in Cordoba duringhis last years. He compiled three sets of astronomicaltables (zījes) of which only one (al-Muqtabis) is extantin a Latin translation made by Johannes of Dumpnoin Palermo (1262). In it he appears as a followerof the Zarqallian tradition, although he often correctshis master’s parameters. Toward 1204, Ibn al-Hā i˒mmakes a strong criticism of one of his other two zījes (al-Amad a˓lā l˒-abad, Valid for all Eternity) because of hisdepartures from Zarqallian orthodoxy. Also extant, inArabic, is a small astrological work in which Ibn al-Kammād studies the problem of the length of humanpregnancy and the determination of the exact moment ofthe conception.

His work was influential in late Maghribean andEgyptian astronomy, for quotations and tabular materi-als from his zījes appear in the thirteenth century zīj ofIbn Ish.āq al-Tūnisī in Abū˒l-H. asan ˓Alī al-Marrā-kushī’s treatise on mīqāt (Astronomy Applied toMuslim Worship) and in a fourteenth century anony-mous Egyptian treatise on the same topic.

See also: ▶Zīj, ▶Ibn al-Hā i˒m

References

Chab’as, José and Bernard R. Goldstein. AndalusianAstronomy: al-Zij al-Muqtabis of Ibn al-Kammâd. Archivefor History of Exact Sciences 48 (1994): 1–41.

Goldstein, Bernard R. and José Chabás. Ibn al-Kammâd’sStar List. Centaurus 38.4 (1996): 317–34.

Mancha, J. L. On Ibn al-Kammad’s Table for Trepidation.Archive for History of Exact Sciences 52 (1998): 1–11.

Millás-Vallicrosa, José M. Las Traducciones Orientales enlos Manuscritos de la Biblioteca Catedral de Toledo.Madrid: Consejo Superior de Investigaciones Científicas,1942. 231–47.

Samsó, Julio. Las Ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992. 320–4.

Vernet, Juan. Un tractat d’obstetricia astrològica. Estudiossobre Historia de la Ciencia Medieval. Ed. J. Vernet.Bellaterra, Barcelona: Universidad de Barcelona-Universidad Autónoma de Barcelona, 1979. 273–300.

Ibn al-Majusı

SAMI KHALAF HAMARNEH

Abū’l-H. asan ˓Alī ibn al-˓Abbās ibn al-Majūsī wasconsidered one of the leading Muslim physicians of histime. He was of Zoroastrian ancestry, and thereforecalled the Magian, and he is known in Latin as Haly˓Abbās. He was born in the old Persian city of Arrajān,in the southwest of Iran, at the end of the first quarter ofthe tenth century. He studied medicine under a leadingmedical tutor (shaykh) named Abū Māhir Mūsā ibnYūsuf ibn Sayyār, who died ca. AD 983.When he had developed a reputation for excellence

and skill, Ibn al-Majūsī was invited to become aphysician-in-ordinary at the palace of King ˓Ad. udal-Dawlah Fannā Khusraw, who reigned from AD 949to 983 in Shīrāz. He was the Buwayhid Shāh whofounded al-˓Ad. udī Bīmāristān, the famous hospital inBaghdad that lasted for almost three centuries. In thatperiod, the Buwayid Dynasty’s power and gloryreached their apex.In recognition of the King’s generosity and patronage

to the sciences and the arts, Ibn al-Majūsī dedicated hismedical encyclopedia, Kāmil al-S. inā a˓h al-T. ibbīyah,known also as Kitāb al-Malikī (Latin Liber regius,presented to the King’s royal library) in Shīrāz.The book comprises two parts, the theoretical and the

practical, each of which has ten treatises. It broughttogether original contributions on public health, preven-tive medicine, dietetics, materia medica, therapy,surgery, clinical observations, and practical medicoethi-cal procedures. Kitāb al-Malikī was first rendered intoLatin by Constantine Africanus (AD 1020–1087) underthe title Pantegni, without giving credit to its original

1094 Ibn al-Nafīs

author. Al-Majūsī was fully recognized when the bookwas translated from Arabic into Latin by Stephen ofAntioch in 1127. Since then, many editions in Latin andArabic have appeared, and a facsimile edition waspublished in 1985 in two volumes.

Among the Arabic compendia on the theme of thehealing arts in Islam, Majūsī’s Kitāb al-Malikī stands asone of the leading texts in its style, systematization, andprecision. It was well read among students and practi-tioners alike. The judge and historian Ibn al-Qift.ī praisedMajūsī by saying that he “excelled in the study ofmedicine, [and] worked hard to comprehend its doctrinesand laws from the original sources.”

Ibn al-Majūsī died in Shīrāz in AH 384/AD 994,leaving behind an essential document in the Arabiclegacy to the history of the medical sciences in thisgolden age.

References

Browne, Edward Granville. Arabian Medicine. Cambridge:Cambridge University Press, 1921.

Gurlt, Ernst. Geschichte der Chirurgie und ihrer AusübungVolkschirurgie, Altterthum,Mittelalter, Renaissance.Vol. 1.Berlin: Hirschwald, 1898.

Hamarneh, Sami Khalaf. Al-Majūsī’s Observations andInstructions on Medicine and Public Health. HamdardMedicus 23.1/2 (1980): 3–36.

Ibn al-Majūsī, ˓Alī ibn al-˓Abbās. Kamil al-S.inā a˓h or Kitābal-Malikī. Arabic ed. in Būlāq, Cairo. 2 vols., AH 1294/AD 1877. Facsimile ed. Frankfurt: Institute for the Historyof Arabic–Islamic Science, 1985.

Ibn al-Majūsī. Discourses 2 and 3 on Anatomy andPhysiology, Liber regius. French trans. P. de Koning.Leiden: Brill, 1903.

Leclerc, Lucien. Histoire de la médecine arabe. Paris:Leroux, 1876 and Rabat, Morocco: Ministry of IslamicAffairs, 1980.

al-Qifti, Jamāl al-Dīn ˓Alī ibn Yūsuf. Tārīkh al-H. ukamā .˒ Ed.Julius Lippert. Leipzig: Weicher, 1903.

Richter, P. Al-Majūsī ‘On Dermatology’. Archiv fur Derma-tologie und Syphilis 113 (1912): 849–64, and 118 (1913):199–208.

Sezgin, Fuat. Geschichte der arabischen Schrifttums. Leiden:Brill, 1967.

Ibn al-Nafıs

ALBERT Z. ISKANDAR

Ibn al-Naf īs, ˓Alā˒ al-Dīn Abu’l-H. asan ˓Alī Ibn Abīal-H. azm al-Qurashī, was born in a village nearDamascus (Syria). He studied medicine at the GreatNūrī Hospital (al-Bīmāristān al-Nūrī) in Damascus,

founded by the Turkish ruler Nūr al-Dīn Mah.mūdIbn Zankī (d. AD 1174). He chose to live, practice,and teach medicine in Egypt, where he eventuallybecame a Chief of Physicians, and was also a personaldoctor to the then-ruler al-Z. āhir Baybars (r. ca. AD1260–1277).

In addition to practicing medicine, he was a Shāfi ī˓jurist, thoroughly educated in Islamic theology andjurisprudence at the Masrūriyya School (Madrasa) inCairo. Hence, he is classed as a “jurist physician,” thusdeviating from the traditional image of the physician–philosopher Galen (d. ca. AD 200), which was sofaithfully emulated by many medieval Arabic-speakingdoctors, as for example al-Rāzī (Rhazes, d. AD 925)and Ibn Sīnā (Avicenna, d. AD 1037).

Ibn al-Nafis was a prolific author. Among his medi-cal works is Kitāb al-Shāmil fi ‘l-s.inā a˓ al-T. ibbiyya(ComprehensiveBook on theArt ofMedicine). He jotteddown preparatory notes for this voluminous book in 300volumes, of which he managed to publish only 80. Itsmanuscripts, so far unpublished, are to be found inCambridge University Library (Cambridge, England),the Bodleian Library (Oxford, England), and al-Muth.afal- I˓rāqī (Iraq). In 1960, three autographed manuscriptsof this bookwere discovered in the LaneMedical Library(Stanford University). The first, referred to by Ibnal-Nafis himself as the 33rdmujallad (bound volume), isdated AH 641/AD 1243–1244. According to the author,the two other manuscripts are its 42nd and 43rd volumes.

It is of historical significance that Ibn al-Nafīs, inKitāb al-Shāmil, divides the procedure to be followedby doctors in surgical operations into three stages:first, the “stage of presentation for clinical diagnosis”;second, the “operative stage”; and third, the “postop-erative period,” during which the patient remainsunder the doctor’s supervision until full recovery isachieved.

Another important work is Sharh. Tashrīh. Kitāb al-Qānūm fi ‘l-T. ibb li-Ibn Sīnā (Commentary on Anatomyin Avicenna’s Canon of Medicine). In it he gives theearliest known account of pulmonary circulation:“…This is the right cavity of the two cavities of theheart. When the blood in this cavity has become thin, itmust be transferred into the left cavity, where thepneuma is generated. But there is no passage betweenthese two cavities, the substance of the heart there beingimpermeable. It neither contains a visible passage, assome people have thought, nor does it contain aninvisible passagewhichwould permit the entry of blood,as Galen thought. The pores of the heart there arecompact and the substance of the heart is thick. Itmust, therefore, be that when the blood has becomethin, it is passed into the arterial vein (pulmonary artery)to the lung, in order to be dispersed inside the

Ibn al-Quff (al-Karakī) 1095

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substance of the lung, and to mix with the air. The finestparts of the blood are then strained, passing into thevenous artery (pulmonary vein) reaching the left of thetwo cavities of the heart, after mixing with the air andbecoming fit for the generation of pneuma…”

Ibn al-Naf īs’ discovery of pulmonary circulationantedates the accounts mentioned by Michael Servetus(AD 1553), Realdo Colombo (AD 1559), and AndreaCesalpino (d. AD 1603). Andreas Vesalius (d. AD1564), who does not mention blood circulation, refutesGalen in his statement: “…I do not see how even thesmallest amount of blood could pass from the rightventricle to the left ventricle, through the interventricu-lar septum…” We now say it was William Harvey(d. AD 1657) who, through experimentation whichlasted almost 20 years, discovered the entire path ofblood circulation.

Ibn al-Nafīs wrote a large textbook, Al-Muhadhdhabfi ‘l-Kuh. l al-Mujarrab (The Polished Book on Experi-mental Ophthalmology), divided into two sections: “Onthe Theory of Ophthalmology,” followed by detailedaccounts of “Simple and Compounded OphthalmicDrugs.”

A very popular and concise book was Ibn al-Nafīs’Mūjiz al-Qānūn fi ‘l-T. ibb (Abstract of Ibn Sīnā’sCanon of Medicine). It has been claimed – probablyunfairly – that the tedious prolixity of Ibn Sīnā’s Canonof Medicine, together with the incomprehensibilityof some of its statements, and Ibn al-Nafīs’ Abstract ofAvicenna’s Canon of Medicine, with its undue brevityand popularity among Arabic-speaking students ofmedicine, led to the decline of late medieval medicaleducation.

On the philosophy of religion, Ibn al-Nafīs wroteAl-Risāla al-Kāmiliyya fi’l-Sīra al-Nabawiyya (Missiveon the Complete Prophetic Conduct), also known bythe title Fād. il Ibn Nāt.iq. It was written along the linesof Ibn T. ufayl’s (d. AD 1185) H. ayy Ibn Yaqz.ān. In it,Ibn al-Nafīs imagines the generation – inside a cave ona deserted island – of a human being. The author guidesthe reader to the way in which this lone human beingwould arrive at the discovery of science and philoso-phy, then the knowledge of prophecies, and particularlythe Sīra (conduct) of the Prophet Muh.ammad, and thelegal doctrines of Islam.

In his old age, Ibn al-Nafīs bequeathed his ownhouse, including an extensive private library, to theQalāwūn Hospital, founded in AD 1284 by SultanQalāwūn (r. AD 1279–1290). Ibn al-Nafīs died in his80s, a bachelor who devoted all his time to the practiceof medicine on which he wrote several books. He diedon 17th December 1288 (11th Dhu’l-Qa d˓ah 687).

See also: ▶Ibn Sīnā, ▶al-Rāzī

References

Abdul-Aziz, L. A. S. Does History Repeat Itself in Medicine?Postgraduate Medical Journal 77.913 (2001): 743.

Abou Aly, Amal. A Few Notes on Hunayn’s Translation andIbn al-Nafis’ Commentary on the First Book of the‘Aphorisms’. Arabic Sciences and Philosophy: A Histori-cal Journal 10.1 (Mar. 2000): 139–50.

Adler, Robert E. Medical Firsts: From Hippocrates to theHuman Genome. Hoboken, New Jersey: John Wiley &Sons, 2004.

Al-Ghazal, Sharif Kaf. The Discovery of the PulmonaryCirculation: Who Should Get the Credit: Ibn al-Nafis orWilliam Harvey. Journal of the International Society for theHistory of Islamic Medicine (ISHIM) 1.2 (Oct. 2002): 46–8.

Al-Wafā˒ī, Muh.ammad Z. āfir and Muh.ammad Ruwās Qal j˓ī,eds. Al-Muhadhdhab fi’l-Kuh. l al-Mujarrab li- A˓lī (Ibn al-Nafīs). Casablanca: Al-Najāh. al-Jadīdah Press, Manshūrātal-Munaz.z.ama al-Islāmiyya li-l-Tarbiya wa’l-˓Ulūm wa’l-Thaqāfa (Isīkū), 1988.

Ibn al-Nafīs, ˓Alā˒ al-Dīn. Mūjiz al-Qānūn. Calcutta: Educa-tion Press for Committee of Public Instruction 1828.

Iskandar, Albert Zaki. Ibn al-Nafīs. Dictionary of ScientificBiography. Vol. 9. New York: Scribner’s Sons, 1970–1980. 602–6.

Nassar, Munir E. William Harvey and the Circulation ofthe Blood. Journal of the Royal Society of Medicine 89(1996): 178.

Saidi, Farrokh. Ibn Al-Nafis. Journal of the Royal Society ofMedicine 91.9 (Sept. 1998): 508.

Ibn al-Quff (al-Karakı)

SAMI K. HAMARNEH

Abū’l-Faraj ibn Ya q˓ūb ibn Ish.āq Ibn al-Quff al-Karakīwas born on the 22nd of August 1233, in the city ofKarak (hence the name al-Karakī) in the district ofTransjordan in larger Syria (Bilād al-Shām). The firstand most intimate biography, by a friend of al-Karakī’sfamily, was by Abū’l-Faraj’s first teacher in the healingart – the prominent physician and historian of medicineIbn Abī Us.aybi a˓h (d. 1270). The meeting between al-Karakī’s family and Us.aybi a˓h took place in S.arkhad,Syria. As Us.aybi a˓h was the physician-counselor tothe governor (wālī ) of S.arkhad and the entire province,al-Karakī’s family moved from Karak north to S.arkhad.The father was summoned by the governor to serve asa secretary to the Department of Welfare (dīwān al-birr). A very close friendship developed between thephysician as a leading and resourceful practitioner, andYa q˓ūb al-Karakī as an able secretary, adviser, histori-an, linguist, and man of letters.At that time, the son Abū’l Faraj was 11 or 12 years

of age, a bright fellow who had acquired the basics in

1096 Ibn al-Quff (al-Karakī)

education in Karak. The father asked the physician if hewould teach his son the healing art, and Us.aybi a˓hwillingly accepted the challenge. He soon taught himthe basics of the field: the theory and practical aspectsof medicine, methods of treatment, and the identifica-tion of causes and symptoms of diseases.

The major texts which were studied included someof the writings of Hippocrates (known as the Hippocraticcorpus, such as the Aphorisms and Prognoses) and someof themedically important catechisms, such asAl-Masā i˒lby H. unayn ibn Ish.āq (809–873), and the major writingsof al-Rāzī (Latin Rhazes, 865–925), particularly theclinical and therapeutic texts.

After the fall of the S.arkhad province into the handsof the Ayyūbid King, al-S.ālih. Najm al-Dīn (1245–1249), al-Karakī’s family moved to Damascus (theSyrian capital of the Ayyūbids) where the father waspromoted to a higher position. The son continued hisstudy under some of the most illustrious physicians atthe time. Damascus had great hospitals, including thehospital located in the Citadel for the Royal family,civil servants, and army personnel. There Ibn al-Quffhad his training to become a physician.

This medieval period had witnessed great cultural,political, and technoscientific changes. There was thefall of the prestigious Fātimid. (Shī i˓te) dynasty inCairo, and the rise of the Ayyūbid (Sunnite) dynasty inCairo and Damascus under the leadership of SultānS.alāh. al-Dīn (Saladin, r. 1171–1193) and his succes-sors. There was also the rise of the Bahri Mamluks(slave sultans 1250–1381). However, the true founderof the “Slave” dynasty was Sultān al-Z. ahir Baybars(d. 1277), who was first purchased to serve in theAyyūbid army and then became their ruler. During thistime, the healing arts reached new heights.

Having had excellent training and having become aworthy practitioner-surgeon, Ibn al-Quff was sum-moned in about 1262 (at the age of 29) to be thephysician-surgeon in ˓Ajlūn, his home country inTransjordan. There he served the profession for adecade, at the end ofwhich he published his firstmedicalencyclopedia Al-Shāf ī-al-T. ibb (The Comprehensiveof the Healing Arts), completed in early 1272. It iscomposed of 12 treatises encompassing the entiremedical field. It was a significant contribution to thefield at the time and containedmany timely observationsand innovations.

From ˓Ajlūn, al-Karakī was summoned to the Syriancapital, Damascus. There he served at its Citadel andhospital from 1272 until his untimely death in early July1286 at the age of 52. We know that many medicalstudents came to hear his lectures and listen to hiseloquence. He also continued to fulfill his duty in caringfor the sick and the wounded and continued his researchand publications. Among these are two commentaries:

one on the Hippocratic Aphorisms, entitled al-Us.ūl,edited in Cairo, and the other a commentary on thegeneralities of theQānūn of Ibn Sīnā (d. 1037). The lastSharh was complete about 1274.

His other work is Jami˓ al-Gharad. , on preventivemedicine and the preservation of health in 60 chapters,completed about 1275. It is extant in several manu-scripts. This is possibly the finest work of its kind inmedieval times, and it needs translation into English forwider audiences.

Al-Karakī’s best and most renowned manual isal-˓Umdah on surgery. It was published in Hyderabad,India, in 1356 AH/1937 and ranks second after al-Tas.rīf(The Thirtieth Treatise) by al-Zahrāwī (Abulcasis,ca. 939–1013).

Only recently have al-Karakī’s literary contributionsbegun to draw wider recognition. His writings shouldplace him among the greatest physician-surgeonsand public health experts during the Arab-IslamicGolden Age.

See also: ▶Ibn al-Majūsī

References

Brockelmann, Carl. Geschichte der arabischen Litteratur.Vol. 1. Leiden: E. J. Brill, 1943. 649; and Supplement 1(1937): 899.

Clot, Antoine B. Compte rendu des travaux de l’école demédecine d’A. Zabel (Egypt). Paris: Cavellin, 1833. 117–78.

El-Gammal, Samir Yahia. Preparation of Ethereal Oils(al-Duhoun) by Ibn al-Quff (13th century A.D.). Bulletinof the Indian Institute of the History of Medicine26.1–2 (Jan.–July 1996): 59–64.

Hamarneh, Sami K. The Physician, Therapist and Surgeon –Ibn al-Quff (al-Karakī 1233–1286), an Introductory Surveyof his Time, Life and Works. Cairo: The Atlas Press, 1974.

---. Nutritions and Dietetics in Ibn al-Quff al-Karakī’sWritings. Hamdard 3.4 (1990): 23–37.

---. Ibn al-Quff’s Contributions to Arab-Islamic MedicalSciences. Hamdard 3.1 (1991): 27–36.

---. Ibn al-Quff al-Karaki and His “al-‘Umdah” (On Surgery),Completed 680 A.H./1281. Journal of the History ofArabic Science 11 (1997): 75–88.

---. Innovations, Techniques and Commentaries on Ibn al-Quffal-Karaki’s Surgical Manual ‘Al-“Umdah’ (ca. 1281).Hamdard Medicus 41.1 (Jan.-Mar. 1998): 5–21 (facsims).

Ibn Abī Us.aybi a˓h. ˓Uyūn al-Anbā f˒i T. abaqāt al- A˓tibbā .˒Vol. 2. Cairo: Būlāq Edition, 1299 AH/1882. 273–4.

Ibn al-Quff al-Karakī. Book on Preventive Medicine and thePreservation of Health. Ed. S. K. Hamarneh. Amman:University of Jordan Press, 1989.

Leclerc, Lucíen. Histoire de la médecine Arabe. Vol. 2. Paris:Leroux, 1876. 203–4.

Sarton, George. Introduction to the History of Science.Baltimore: Williams and Wilkins, 1927.

Sobhy, Georgy. The Arabian Surgeon Ibn al-Quff. MedicalAssociation of Egypt 20 (July 1937): 349–57.

Ibn Al-Shāt.ir 1097

Ibn al-Raqqam

I

JULIO SAMSÓ

Muh.ammad ibn al-Raqqām al-Andalusī (d. 1315) wasan Andalusian astronomer, mathematician, and physi-cian. He was probably born in Murcia and left the citywhen it was conquered by Alfonso X in 1266. He livedin Bejaia (Algeria), Tunis and, after 1280, accepted theinvitation of Muh.ammad II (1273–1302) and estab-lished himself in Nas.rid Granada where he taughtmathematics and astronomy (as well as medicine andlaw). Among his students in astronomy we find kingNas.r (1309–1314). His son, Ibrāhīm ibn Muh.ammadibn al-Raqqām, was an astrolabe maker: one of hisinstruments (made in Guadix in 1320) is still preservedin Madrid.

Among his extant workswe shouldmention hisRisālafī I˓lm al-Z.ilāl (Treatise on the Science of Shadows)as well as two sets of astronomical tables (zījes), the firstofwhichwas probably compiled inBejaia in 1280–1281,while the second was made in Tunis and later adaptedto the coordinates of Granada. His book on Shadows is abrilliant treatise on Gnomonics where Ibn al-Raqqāmexplains how to build all kinds of sundials (amongwhichwe find a portable sundial which includes a compass)using projections on a plane which, ultimately, derivefrom Ptolemy’s Analemma. The first of his zījes, entitledal-Zīj al-Shāmil fī Tahdhīb al-Kāmil (A General Set ofAstronomical Tables inwhich [Ibn al-Hā'im’s] Kāmil Zījis Corrected), follows narrowly the theoretical contentsof Ibn al-Hā i˒m’s al-Zīj al-Kāmil fī’l-Ta ā˓līm to whichIbn al-Raqqām adds the numerical tables which had beenlost in themanuscript of Ibn al-Hā'im’s work. His secondzīj al-Zīj al-Qawīm fī Funūn al-Ta d˓īl wa-l-Taqwīm (TheSolid Handbook to Calculate Equations and PlanetaryPositions) is a summary and adaptation of the first one tothe coordinates of Tunis and Granada. Both works bearwitness to the diffusion of Ibn al-Zarqāllu’s astronomicalideas in the Maghreb and Andalusia.

See also: ▶Ibn al-Zarqāllu, ▶Alfonso X, ▶Zīj,▶Sundials

References

Carandell, Joan. Analemma for the Determination of theAzimuth of the Qibla in the Risāla fī I˓lm al-Z. ilāl of Ibnal-Raqqām. Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften 1(1984): 61–72.

---. Risāla fi i˓lm al-Z. ilāl de Muh. ammad ibn al-Raqqām al-Andalusī. Barcelona: Instituto Millás-Vallicrosa de Histor-ia de la Ciencia Arabe, 1988.

Kennedy, E. S. The Astronomical Tables of Ibn al-Raqqam:A Scientist of Granada. Zeitschrift für Geschichte derArabisch-Islamischen Wissenschaften Bd 11 (1997): 35–72.

Samsó, Julio. Las Ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992. 414–5, 421–7.

Ibn Al-Shat.ir

DAVID A. KING

Ibn al-Shāt.ir, A˓lā˒ al-Dīn A˓lī ibn Ibrāhīm was born inDamascus ca. 1305. He was the most distinguishedMuslim astronomer of the fourteenth century. Althoughhe was head muwaqqit at the Umayyad mosque inDamascus, responsible for the regulation of the astrono-mically defined times of prayer, his works on astronomi-cal timekeeping are considerably less significant thanthose of his colleague al-Khalīlī. On the other hand, Ibnal-Shāt.ir made substantial advances in the design ofastronomical instruments. Nevertheless, his most signifi-cant contribution to astronomy was his planetary theory.In his planetary models Ibn al-Shāt.ir incorporated

various ingenious modifications of those of Ptolemy.Also, with the reservation that they are geocentric, hismodels are the same as those of Copernicus. Ibn al-Shāt.ir’s planetary theory was investigated for the first timein the 1950s, and the discovery that his models weremathematically identical to those of Copernicus raisedthe very interesting question of a possible transmissionof his planetary theory to Europe. This question hassince been the subject of a number of investigations,but research on the astronomy of Ibn al-Shāt.ir and hissources, let alone on the later influence of his planetarytheory in the Islamic world or Europe, is still at apreliminary stage.Ibn al-Shāt.ir appears to have begun his work on

planetary astronomy by preparing a zīj, an astronomicalhandbook with tables. This work, which was based onstrictly Ptolemaic planetary theory, has not survived. Ina later treatise entitled Ta l˓iq al-ars.ād (Commentson Observations), he described the observations andprocedures with which he had constructed his newplanetary models and derived new parameters. No copyof this treatise is known to exist in the manuscriptsources. Later, in Nihāyat al su l˒ f ī tas.h. ih. al-us.ūl (AFinal Inquiry Concerning the Rectification of PlanetaryTheory), Ibn al Shāt.ir presented the reasoning behind hisnew planetary models. This work has survived. Finally,Ibn al-Shāt.ir’s al-Zīj al-jadīd (The New AstronomicalHandbook), extant in several manuscript copies, con-tains a new set of planetary tables based on his newtheory and parameters.

1098 Ibn Al-Shāt.ir

Several works by the scholars of the mid-thirteenthcentury observatory at Maragha are mentioned in Ibnal-Shāt.ir’s introduction to this treatise, and it is clear thatthese were the main sources of inspiration for his ownnon-Ptolemaic planetary models.

The essence of Ibn al-Shāt.ir’s planetary theory is theapparent removal of the eccentric deferent and equantof the Ptolemaic models, with secondary epicycles usedinstead. The motivation for this was at first sightaesthetic rather than scientific, but his major work onobservations is not available to us, so this is not reallyverifiable. In any case, the ultimate object was toproduce a planetary theory composed of uniform mo-tions in circular orbits rather than to improve thebases of practical astronomy. In the case of the sun,no apparent advantage was gained by the additionalepicycle. In the case of the moon, the new configurationto some extent corrected the major defect of thePtolemaic lunar theory, since it considerably reducedthe variation of the lunar distance. In the case of theplanets, the relative sizes of the primary and secondaryepicycles were chosen so that the models weremathematically equivalent to those of Ptolemy.

Ibn al-Shāt.ir also compiled a set of tables displayingthe values of certain spherical astronomical functionsrelating to the times of prayer. The latitude used forthese tables was 34°, corresponding to an unspecifiedlocality just north of Damascus. These tables displaysuch functions as the duration of morning and eveningtwilight and the time of the afternoon prayer, as well asstandard spherical astronomical functions.

Ibn al-Shāt.ir designed and constructed a magnificenthorizontal sundial that was erected on the northernminaret of the Umayyad Mosque in Damascus. Theinstrument now on the minaret is an exact copy made inthe late nineteenth century. Fragments of the originalinstrument are preserved in the garden of the NationalMuseum, Damascus. Ibn al-Shāt.ir’s sundial, made ofmarble and a monumental 2 × 1 m in size, bore acomplex systemof curves engraved on themarblewhichenabled the muwaqqit to read the time of day inequinoctial hours since sunrise or before sunset or withrespect to either midday or the time of the afternoonprayer, as well as with respect to daybreak and nightfall.The gnomon is aligned towards the celestial pole,a development in gnomonics usually ascribed toEuropean astronomers.

A much smaller sundial forms part of a compendiummade by Ibn al-Shāt.ir, now preserved in Aleppo. It iscontained in a box called s.andūq al-yawāqīt (jewelbox), measuring 12 × 12 × 3 cm. It could be used tofind the times (al-mawāqīt) of the midday and afternoonprayers, as well as to establish the local meridian and thedirection of Mecca.

Ibn al-Shāt.ir wrote on the ordinary planisphericastrolabe and designed an astrolabe that he called al-āla

al-jāmi a˒ (the universal instrument). He also wroteon the two most commonly used quadrants, theastrolabic and the trigonometric varieties. Two specialquadrants which he designed were modifications ofthe simpler and ultimately more useful sine quadrant.One astrolabe and one universal instrument actuallymade by Ibn al-Shāt.ir survive.

A contemporary historian reported that he visitedIbn al-Shāt.ir in 1343 and inspected an “astrolabe” thatthe latter had constructed. His account is difficult tounderstand, but it appears that the instrument wasshaped like an arch,measured three-quarters of a cubit inlength, and was fixed perpendicular to a wall. Part ofthe instrument rotated once in 24 h and somehowdisplayed both the equinoctial and the seasonal hours.The driving mechanism was not visible and probablywas built into the wall. Apart from this obscurereference, we have no contemporary record of anycontinuation of the sophisticated tradition of mechan-ical devices that flourished in Syria some 200 yearsbefore his time.

Ibn al-Shāt.ir died in Damascus ca. 1375. Laterastronomers in Damascus and Cairo, none of whomappears to have been particularly interested in his non-Ptolemaic models, prepared commentaries on, and newversions of, his zīj. In its original form and in variousrecensions this work was used in both cities for severalcenturies. His principal treatises on instrumentsremained popular for several centuries in Syria, Egypt,and Turkey, the three centers of astronomical time-keeping in the Islamic world. Thus his influence in laterIslamic astronomy was widespread but, as far as we cantell, unfruitful. On the other hand, the reappearance ofhis planetary models in the writings of Copernicusstrongly suggests the possibility of the transmission ofsome details of these models beyond the frontiersof Islam.

See also: ▶al-Khalīlī, ▶Zīj, ▶al-Jazarī, ▶AstronomicalInstruments

References

Primary SourcesZīj of Ibn al-Shāt.ir. MS Oxford Bodleian A30.

Secondary SourcesBrockelmann, Carl. Geschichte der arabischen Litteratur.2 vols., 2nd ed. Leiden: E. J. Brill, 1943–1949, and 3suppl. vols. Leiden: E. J. Brill, 1937–1942, II, p. 156, andsuppl. II, p. 157.

Hartner, Willy. Trepidation and Planetary Theories: CommonFeatures in Late Islamic and Early Renaissance Astrono-my. Accademia Nazionale dei Lincei, 13° Convegno Volta,1971. 609–29.

Janin, Louis. Le cadran solaire de la Mosquée Umayyade àDamas. Centaurus 16 (1971): 285–98.

Ibn al-Yāsamīn 1099

I

Janin, Louis, and D. A. King. Ibn al-Shāt.ir’s s.andūqalyawāqīt: An Astronomical “Compendium.” Journal forthe History of Arabic Science 1 (1977): 187–256, reprintedin King, D. A. Islamic Astronomical Instruments. London:Variorum, 1987, XII.

Kennedy, Edward S. A Survey of Islamic AstronomicalTables. Transactions of the American PhilosophicalSociety, n.s. 46.2 (1956): 121–77.

Kennedy, Edward S. and Imad Ghanem. The Life and Work ofIbn al-Shāt.ir, anArabAstronomerof the FourteenthCentury.Aleppo: Institute for History of Arabic Science, 1976.

Kennedy, Edward S. et al. Studies in the Islamic ExactSciences. Beirut: American University of Beirut, 1983.

King, David A. Ibn al-Shāt.ir. In Dictionary of ScientificBiography, Vol. 12. New York: Charles Scribner’s Sons,1975, 357–364.

---. A Survey of the Scientific Manuscripts in the EgyptianNational Library. Winona Lake, Indiana: Eisenbrauns,1986. C30.

---. The Astronomy of the Mamluks. Isis 74 (1983): 531–555,reprinted in King, D. A. Islamic Mathematical Astronomy.London: Variorum; 2nd revised ed., Aldershot: Variorum,1993, III.

---. L'astronomie en Syre à l’époque islamique. Syrie –mémoire et civilisation. In Ed. S. Cluzan et al. Paris:Institut du Monde Arabe, 1993. 391–392, 435, and 439.

---. In Synchrony with the Heavens: Studies in AstronomicalTimekeeping and Instrumentation in Medieval IslamicCivilization, Vol. 1: The Call of the Muezzin (Studies I–IX).Leiden: Brill, 2004; Vol. 2 Instruments of Mass Calcula-tion (Studies X–XVIII). Leiden: Brill, 2005.

King, David A. and Julio Samsó, with a contribution byBernard R. Goldstein. Astronomical Handbooks and Tablesfrom the Islamic World (750–1900): An Interim Report.Suhayl – Journal for the History of the Exact and NaturalSciences in IslamicCivilisation (Barcelona) 2 (2001): 9–105.

Saliba, George. Theory and Observation in Islamic Astrono-my: The Work of Ibn al-Shāt.ir of Damascus (1375).Journal for the History of Astronomy 18 (1987): 35–43.

---. A History of Islamic Astronomy. Planetary TheoriesDuring the Golden Age of Islam. New York: New YorkUniversity Press, 1994.

Schmalzl, Peter. Zur Geschichte des Quadranten bei denArabern. Munich: Salesianische Offizin, 1929.

Suter, Heinrich. Die Mathematiker und Astronomen derAraber und ihre Werke. Leipzig, 1900, reprinted Amster-dam: Oriental Press, 1982. 416.

Ibn al-Yasamın

AHMED DJEBBAR

The name of this mathematician is Abū Muh.ammad‘Abdallāh ibn Muh.ammad ibn Hajjāj al-Adrīnī, morecommonly known as Ibn al-Yāsamīn. As his nameindicates, he was originally from a Berber tribe fromthe Maghreb (North Africa), and, according to IbnSa ī˓d, he was black like his mother. We know nothingabout the exact date of his birth, but can reasonably

place it in the second half of the twelfth century. Wealso know nothing specific about his place of birth,which could have been in the Andalus (Spain) or theMaghreb. But since some historians have given himthe surname al-Ishbīlī, he may have been born or grownup in Seville. In any case, Ibn Sa ī˓d states that hisformative education occurred in Seville.This education was not restricted to mathematics,

since we know he also became famous in the fields oflaw and literature, particularly in the Andalusian poetryof the Muwashshah.āt. That being said, however, weknow nothing of the context in which he received thisrich education nor of his teachers. The only informationwe have is from Ibn al-Yāsamīn himself about one ofhis professors, Abū ˓Abdallāh Muh.ammad ibn Qāsimal-Shalūbīn, who taught him algebra and the science ofcalculation.We also do not know exactly when Ibn al-Yāsamīn

began to publish his mathematical writings. Ibn al-Abbār tells us only that Ibn al-Yāsamīn’s famousalgebraic poem was drafted in Seville and that, in 1190also in Seville, he was using it in his teaching.Concomitant with his mathematical activities was

Ibn al-Yāsamīn’s dedication to poetry, and accordingto Ibn Sa ī˓d, some of his poems had even been setto music and sung at this time. It may have been hisliterary success which led to his frequenting thecourt of the third Almohad caliph Abū Yūsuf Ya q˓ūb(1184–1199) and of his successor Muh.ammad al-Nās.ir(1199–1213). These frequent court visits and the fameof his literary and mathematical publications probablygained Ibn al-Yāsamīn some enemies. Also some of hiscontemporaries accused him of leading a dissolute life.But none of these can be seen as the cause of hisassassination in 1204 in Marrakesh.

The Mathematical Writings of Ibn al-YasamınThe best-known work of Ibn al-Yāsamīn is a poemof 53 verses in rajaz meter entitled al-Urjūza al-yāsmīnīyya fi al-jabr wa ‘l-muqābala (Poem onAlgebraand Restoration). In it the author defines the algebraknown in his time – number, root, and sequence, thenthe six canonical equations of al-Khwārizmī with theprocesses of solving them, and finally, the operationsof algebra – the restoration, comparison, multiplication,and division of monomials.This poem has been widely read throughout the

centuries both within the Maghreb and beyond. Thus,there are many commentaries on it by other famousmathematicians such as Ibn Qunfudh (d. 1407) andal-Qalas.ādī (d. 1486) in the Maghreb, Ibn al-Hā i˒m(d. 1423) and Sibt. al-Māradīnī (d. 1501) in Egypt andelsewhere.For a long time, the contribution of Ibn al-Yāsamīn

to mathematics was known only through his Urjūza in

1100 Ibn Al-Zarqāllu

algebra. It is quite possible, moreover, that it wasthe success of this poem which led him to write asecond one on irrational quadratic numbers and maybea third on the method of false position. But thedistribution of these last two poems was relativelymodest, compared to that of the first one, and asidefrom the rare copies that exist, we have not yet foundany explicit reference to the contents of the two otherpoems in any works on calculation written after thetwelfth century.

The same situation exists for Ibn al-Yāsamīn’s fourthwritten work on mathematics, entitled Talqīh. al-afkārbi rushūm h. urūf al-ghubār (Fertilization of Thoughtswith the Help of Dust Letters [Hindu Numerals]). Thiswork is much more important than his poems, as muchin quantity as in quality. Indeed, it is a book of 200folios which contains classic chapters on the science ofcalculation and on geometry. Among the works of theMuslim West which have come down to us, it is theonly one which consolidates these two disciplines. Itsimportance is also due the nature of its materials and itsmathematical tools which make it an original book andalso one which is totally representative of this period oftransition in which three mathematical traditions werejuxtaposed– of the East, theAndalus, and theMaghreb–before they became blended in the same mold.

For example, the following elements contribute bothto the originality of his work and to its being anchoredin the great Arab mathematical tradition of the ninth toeleventh centuries:

In arithmetic, contrary to the Maghrebian traditionwhich prevailed from the fourteenth century on, Ibn al-Yāsamīn treats multiplication and division first, beforeaddition and subtraction. This approach, which can befound again later in the work of Ibn al-Zakariyā’ al-Gharnāt.ī, seems to be based on Andalusian mathemati-cal practice.

For fractions, the remarks and suggestions of Ibn al-Yāsamīn concerning the reading of certain expressionsdemonstrate that the symbolism of fractions had notbeen established definitively in his time. This was notthe case, it appears, for the symbolism of equationswhich had been established relatively early, since thereis no difference between the symbols used in the Talqīh.al-afkār of Ibn al-Yāsamīn and those used in theBughyat at.-t.ullāb (The Hope of Students) of Ibn Ghāzīal-Miknāsī (d. 1513).

As for the presence of geometry in a work on thescience of calculation, this is not exceptional in regardto the Arab mathematical tradition, viewed in itsentirely, in so far as similar chapters (i.e., chapterswhich deal with problems in metric geometry) hadalready been inserted in works edited in the East, suchas the Takmila fi l-h. isāb (Complement to Calculus) of˓Abd al-Qāhir al-Baghdādī or the Kitāb al-Kāf ī (TheSufficient Book) by al-Karajī.

In spite of what we have noted about the contentsof Talqīh. al-afkār, there has not been any explicitreference to the book in Maghrebian mathematicalwriting. There could be at least two possible explanationsfor this. First, a break in the tradition whose cause is to befound outside the scientific milieu of that time. Thishypothesis is not implausible if one takes into accountthe personality of Ibn al-Yāsamīn and his controversialbehavior and also his close ties to Almohad power.

The second reason, which is also plausible and whichcan be added to the first, can be found in mathematicalpractice after Ibn al-Yāsamīn, a practice which borethe strong imprint of mathematicians from Marrakesh,like Ibn Mun i˒m (d. 1228), al-Qād. i al-Sharīf (d. 1282–1283), and Ibn al-Bannā˒ (d. 1321). We have observedthis same phenomenon of the absorption of a mathemat-ical tradition first in the East with the first writtenArab arithmetical works from the ninth century and, inparticular, with the work of al-Khwārizmī, and then inthe Andalus with writings of the tenth century, like thoseof al-Majrīt.ī and his pupils.

See also: ▶Ibn al-Banna ,˒ ▶al-Majrītī, ▶al-Karajī

References

Djebbar, A. Quelques aspects de l’algèbre dans la traditionmathématique arabe de l’Occident musulman. Actes duPremier Colloque Maghrébin d’Alger sur l’Histoire desmathématiques arabes. Alger, 1986. Alger: Maison duLivre, 1988. 99–123.

Guergour, Y. Étude comparative entre deux commentaires duTalkhīs. d’lbn al-Bannā :˒ celui d’lbn Qunfudh et celui d’lbnZakariyā al-Gharnāt.ī. 5e Symposium International sur lesSciences Arabes. Proceedings of the Symposium, Grenada,1992 (in press).

Ibn al-Abbār. At-Takmila li kitāb as.-S. ila. Ed. I˓zzat al-˓At.t.āral-H. usaynī. Cairo: Mat.ba a˓t as-sa ā˓da, 1956. 43.

Ibn Sa ī˓d. Al-Ghus.ūn al-yāni ā˓ fī mah.āsin shu a˓rā’ al-mi’aas-sābi a˓. Ed. Ibrāhīm al-Ibyārī. Cairo: Dār al-ma ā˓rif,1945. 42, 47.

Jalāl Shawqī. Manz.ūmāt Ibn al-Yāsamīn fī a˓māl al-jabr wal-h. isāb. Kuwait: Mu’assassat al-Kuwayt li t-taquaddumal- i˓lmī, 1988.

Souissi, M. Al-lum a˓ al-māradīniyya fī sharh. al-Yāsamī-niyya. Kuwait, 1988.

Zemouli, T.Mu’allafāt Ibn al-Yāsamīn ar-riyād. iyya. Master’sThesis, E.N.S. d’Alger, 1993.

Ibn Al-Zarqallu

EMILIA CALVO

Ibn al-Zarqāllu, Abū Ish.āq Ibrāhīm ibn Yah.yā al-Naqqāsh, sometimes known as Azarquiel, was born inthe first quarter of the eleventh century to a family of

Ibn Bat.t.ūt.a 1101

I

artisans. He entered the service of the qād. ī (judge) S.ā i˓dof Toledo first as an artisan, and after as the directorof a group which carried out astronomical observa-tions. Ibn al-Zarqāllu lived in Toledo until ca. AD 1078,when he moved to Cordoba where he composed hislast works under the patronage of the king of Sevillaal-Mu t˓amid ibn ˓Abbād and where he died in AD1100. His work exerted considerable influence on laterauthors such as Ibn al-Kammād, Abū’l-H. asan ˓Alī Ibnal-Bannā’, Abraham ibn E˓zra, Ibn al-Hā i˒m, Ibn Ish.āq,and Ibn Bās.o.

Ibn al-Zarqāllu’s works are basically astronomical,although an astrological treatise by him is also extant.Other works of Ibn al-Zarqāllu are described below:

The Almanac is a reelaboration by Ibn al-Zarqāllu ofthe work of an unknown author called Awmātiyūs.It allows the determination of planetary longitudes,without computation, by combining Ptolemaic para-meters with the Babylonian doctrine of the goal-years.The goal-years consisted of cycles peculiar to eachplanet. These cycles included an entire number of solaryears which, in turn, comprised an exact number ofsynodic and zodiacal revolutions. These cycles wereknown by the Babylonian astronomers, and they arealso found in Ptolemy’s Almagest. The advantage ofthese cycles for astronomers is that the positions of theplanets can be calculated for a complete cycle whichwill be repeated, so these positions will always be thesame for a given date within the cycle.

Treatise on the Motion of the Fixed Stars is preservedin a Hebrew translation. It is probably the most com-plete medieval text on the trepidation theory. Trepida-tion consists of a back-and-forth vibration within fixedlimits, which is supposed to account for the variation invelocity of the slow eastward motion observed in thefixed stars. The treatise proposed three different geo-metrical models to demonstrate this theory.

Fīsanat al-śams (On the Solar Year) was probablywritten between AD 1075 and 1080 and based on25 years of solar observations. Here Ibn al-Zarqālluestablished the proper motion of the solar apogee to beof 1° in 279 Julian years. The text is lost but it can bereconstructed from the works of later astronomerslike Ibn al-Kammād, Ibn al-Hā i˒m, Ibn Ish.āq, Ibnal-Raqqām and Ibn al-Bannā .˒

Risālat al-s.af īh. a al-zarqāliyya (Treatise on theZarqaliyya Plate) and Risālat al-s.afih. a al-shakkāziyya(Treatise on the Shakkāziyya Plate) are two treatises onthe use of a universal astrolabe called s.af īh. a (plate).There is an Alphonsine translation in the Libros delSaber de Astronomia of the treatise on the use of thes.af īh. a zarqāliyya. This instrument offers the possibilityof making calculations for any given latitude by meansof only one plate.

Kitāb al- a˓mal bi’l-s.af īh. a al-zījiyya (Treatise on thePlate for the Seven Planets) describes the equatorium,

an instrument consisting of the representation, drawn toscale, of a planetary model, which is used to determinethe position of a planet at a given moment. Both histreatise on its construction and his treatise on its use areextant.He also took an active part in the elaboration of

the Toledan Tables which seem to have been the resultof the work of a group of astronomers directed by theqād. ī S.ā i˓d.Finally, he was probably the author of a treatise on

the construction of the armillary sphere, translated oradapted by Ish.āq ibn Sīd, which was incorporated intothe Alphonsine Libro de las Armellas.

See also:▶Ibn al-Kammād,▶Ibn al-Bannā ,˒▶Abrahamibn E˓zra, ▶Ibn al-Hā i˒m, ▶Astrolabe, ▶ArmillarySphere

References

Boutelle, M. The Almanac of Azarquiel. Ceniaurus 12 (1967):12–19. Rpt. Studies in the Islamic Exact Sciences. Beirut:American University of Beirut, 1983. 502–10.

Comes, Mercè. Ecuatorios andalusies. Ion al-Samh. , al-Zarqāllu y Abū’l S.alt. Barcelona: Instituto de Cooperacióncon el Mundo Arabe-Universidad de Barcelona, 1991.

Millás Vallicrosa, José María. Estudios sobre Azarquiel.Madrid, Granada: Consejo Superior de InvestigacionesCientíficas, 1943–1950.

Pedersen, F. S. Canones Azarchelis. Some Versions and aText Cahiers de l’Institut du Moyen-Age Grec et Latin, 54.Université de Copenhague, 1987.

Puig, R.Al-s.akkāziyya. Ibn al-Naqqāŝ al-Zarqāllu.Barcelona:Universidad de Barcelona, 1986.

---. Los tratados de construcción y uso de la azafea deAzarquiel.Madrid: InstitutoHispano-ArabedeCultura, 1987.

Samsó, Julio. Las ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992.

Soomer, G. J. The Solar Theory of al-Zarqāl. A History ofErrors. Centaurus 14 (1969): 306–36.

Vernet, J. Al-Zarqāllu. Dictionary of Scientific Biography.Vol. XIV. New York: Charles Scribner’s Sons, 1976. 592–5.

Ibn Bat.t.ut.a

BILAL AHMAD

Ibn Bat.t.ūt.a (1304–1369) was the greatest Muslimtraveler of his time. He was born in Tangier to a well-educated Moroccan family that produced many judges.After receiving basic education in his home town, atage 21 he headed toward Mecca both to make apilgrimage and to study under some notable Muslimscholars in Egypt, Syria, and Hejaz. After reachingEgypt via Tunis and Tripoli, he decided to become atraveler to gain firsthand knowledge about as many

1102 Ibn But.lān

parts of the world as possible. Ibn Bat.t.ūt.a’s fascinationfor travel took him to Syria, Iraq, southern Iran, andAzerbaijan. He then decided to spend the next 3 years(1327–1330) in the holy towns of Mecca and Medinain Hejaz. Ibn Bat.t.ūt.a’s next expedition (1330–1332)started from the seaport of Jidda. He sailed across theRed Sea to Yemen, traveled across Yemen by land, andfrom Aden he sailed along the coast to various tradingports of East Africa. On his way back, he turned hisboat to the Persian Gulf area and concluded this trip byanother pilgrimage to Mecca.

Ibn Bat.t.ūt.a’s travels were supported by the con-tributions of the rulers, governors, and other prominentresidents of the places that he visited. After hearing ofthe benevolence of Muh.ammad bin Tughlaq – the rulerof Delhi, India – Ibn Bat.t.ūt.a decided to go to India.This time he adopted a very unusual route: by movingnorthward, he first passed through Egypt and Syria; hethen traveled extensively in Anatolia (Asia Minor) andthe territories of the Golden Horde where he was wellreceived by the local sultans and other prominentpeople. Ibn Bat.t.ūt.a’s Rih. lah (Book of Travels) providesa clear and lucid picture of Constantinople, Saray (thecapital of the Khan of the Golden Horde), and otherSultanates. After crossing the Steppeswith a caravan, IbnBat.t.ūt.a passed through the towns of Bukhara, Samarkand,Balkh, and Herat. He then crossed the Hindu KushMountains and visited many important towns andcities in the Indus Valley – particularly Sukkur, Multan,and Lahore – before he finally reached Delhi. SultanMuh.ammad bin Tughlaq received him with respect andpresents. The Sultan also appointed him the chiefjustice of Delhi. Ibn Bat.t.ūt.a enjoyed the patronage ofthe Sultan for several years.

In 1342, he appointed Ibn Bat.t.ūt.a the ambassador toChina. After his ship wrecked near Calicut on theMalabar Coast of India, he decided to go to the Maldiveswhere he married into the royal family. In the followingyears, Ibn Bat.t.ūt.a visited Sri Lanka (Ceylon), supportedthe Sultan of the Maldives in a war, went again to theMaldives, and visited Bengal, Assam, and Sumatra. TheSultan of Sumatra provided him with a new ship to go toChina. He arrived at the Chinese port of Zaytun andreached Beijing via the inland waterways. On his returnjourney, he eventually reached Mecca via Sumatra,Calicut, the Persian Gulf, Baghdad, Syria, and Egypt.Ibn Bat.t.ūt.a’s narrative for this entire journey is sketchyand some scholars doubt that he ever reached Beijing.

In April to May of 1349, Ibn Bat.t.ūt.a embarked forhis home from Alexandria via Tunis, Sardinia, andAlgeria. He eventually reached Fez (Morocco), fromwhere he went to the Kingdom of Granada, in Spain.His next destination was western Sudan. After travelingacross the Sahara, he visited the Empire of Mali andreturned to retire in Fez.

Ibn Bat.t.ūt.a was an outstanding adventurer. Hiseducation and experience earned him numerous honorsand awards, including the position of judge in manyparts of the Muslim world. After his retirement, heagain held the office of qād. ī (judge) in a Moroccantown and dictated his recollections to Ibn Juzayy – aroyal poet. Ibn Bat.t.ūt.a’s Rih. lah is a valuable documentfor understanding the ways of life in the fourteenth-century Muslim world.

References

Beazley, C. R. The Dawn of Modern Geography. Vol. 3.Oxford: Clarendon Press, 1906.

Dunn, R. E. The Adventures of Ibn Bat.t.ūt.a: A MuslimTraveller of the Fourteenth Century. London: CroomHelm, 1986.

---. International Migrations of Literate Muslims in the LaterMiddle Period: The Case of Ibn Bat.t.ūt.a. Golden Roads:Migration, Pilgrimage and Travel in Mediaeval andModern Islam. Ed. I. R. Netton. Richmond: Curzon Press,1993. 75–85.

Gibb, H. A. R. The Travels of Ibn Bat.t.ūt.a, AD 1325–1354.3 vols. Cambridge: Cambridge University Press for theHakluyt Society, 1958–1971.

Ibn Bat.t.ūt.a. Rih. lat. Beirut: Dar Sadir, 1964.Newton, A. P. Travel and Travellers of the Middle Ages.London: Kegan Paul, 1930.

Ibn But.lan

ROGER ARNALDEZ

Abū’l-H. asan al-Mukhtār ibn ˓Abdūn ibn Sa d˓ūn IbnBut.lān was a physician, philosopher, and Christiantheologian from Baghdad (eleventh century). He hadfor a teacher a Nestorian priest, Abū’l-Faraj ibnal-T. ayyib, a commentator on Aristotle, Hippocrates,and Galen, who was interested in botany and wrote onthe humors, wine, and natural qualities. Teaching atthe hospital founded in Baghdad by ˓Ad. ud al-Dawla,he directed his pupil in reading and the use ofseveral medical works. He taught him so well thatlater, Ibn But.lān, in a controversy with the physicianIbn Rid.wān, maintained that one could understand thebasic precepts of medicine by simply reading books.

On the subject of the al-Masā i˒l fi’l-T. ibb fi’l-Muta ā˓llimīn (Questions on Medicine for Students)by H. unayn ibn Ish.āq, he believed that Ibn Rid.wān,who had refuted it, had not understood it at all,“because he didn’t study it under the direction ofmasters in this art.” That is why, in spite of his greatknowledge of the works of the Ancients, he refused toconform blindly and to the letter. Also he asked why

Ibn H. awqal 1103

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clear-sighted doctors had lost the habit of caring forcertain maladies, as the Ancients had done, with warmmedicines, and preferred to use cold ones. It seemsalso that Ibn But.lān was instructed in the practiceof medicine by Abū’l-H. asan Thābit ibn Ibrāhīm al-H. arrānī, about whom many praises were said.

Ibn But.lān left Baghdad, crossed Syria, and arrivedin Egypt, where he undertook several polemics withIbn Rid.wān. These covered diverse subjects, touchingin particular the philosophical questions and ideas ofAristotle concerning place, movement, and the soul onwhich Ibn Rid.wān had commented before. He returnedto Constantinople, where he arrived in 446/1054, at thetime of the schism which would eventually separate theGreek from the Latin church. The patriarch MichelCérulaire asked him to edit a treatise on the Eucharistand the use of bread without leavening. That was alsothe year when a terrible epidemic of the plague brokeout in the capital of the Byzantine Empire. Ibn But.lānkept a diary and cited the names of several savants whohad succumbed to it. After this he went to Antiochwhere he directed the establishment of a hospital.Eventually he retired from traveling, and died in460/1068.

His work is very diverse, covering theology,philosophy, logic, and medicine. His interpretation ofthe work of the Ancients is original and animated by acritical spirit. He relied on logic and the grammar oflanguages, and attempted to explain apparent opposi-tion by showing that they had very different pointsof view. Thus Aristotle studied organic forces relativeto their nature, while Galen did so relative to theirperceptible action in the organs which were theirinstruments. Aristotle divided the organs according totheir physical constitution, Galen in relation to theillnesses which affected them. In the same way, withregard to the “egg yolk” color of bile, Ibn But.lān tendedto agree with Galen who explained it by the predomi-nant action of heat, which rends the bile hotter andlighter. On the other hand, H. unayn ibn Ish.āq explainedit as the result of a mixture of bile and phlegm. Thesedifferences can be explained by the ambiguity of theterm muh. h. , which signifies at the same time both theegg yolk alone and the entire interior of the egg, boththe yellow and the white.

Ibn al-Qift.ī retained for us a list of the problems thatIbn But.lān posed. For example, he wondered aboutthe chemical nature of the force of physical attractionbetween lovers. In the field of physiology, he questionedwhy it is that when men dream they are urinating, theywake themselves up without urinating in their beds,while when they dream of a sexual encounter, there is anemission of sperm. He wondered why this was so, whenyou consider how much easier it is to urinate than toejaculate when one is awake.

Ibn But.lān’s most important medical work is theTaqwīn al-s. ih. h. a (Strengthening of Health), a treatiseon hygiene dedicated to general questions on the fourelements, the humors, and the temperaments. Theauthor studied the nature and value of nutrition, as wellas the influence of the environment, water, climate, andhousing on health. The originality of the work lies in itsform: it is presented in small tableaux. It was translatedinto Latin and German. Another noteworthy work isDa a˓t al-At.ibbā (The Physician’s Banquet), on thesubject of medical ethics, which included a satire oncharlatans and ignorant physicians. There is also atreatise on the maladies caused by food, with recom-mended remedies used by monks. Finally, there is atreatise devoted to a discussion of whether a chicken ishotter than a smaller bird.

See also: ▶H. unayn ibn Ish.āq, ▶Ibn Rid.wān

References

Ibn Abī Us.aybi ā˓. ˓Uyūn al-anbā˒ f ī T. abaqāt al-At.ibbā(Sources of Information on the Classes of Physicians).Bayrūt: Dār Maktabat al-Hayāh, 1965.

Ibn al-Qift.ī. Ta r˓īkh al-H. ukamā (History of Philosophy). Ed.J. Lippert. Leipzig: Dieterichische Verlagsbuchshandlung,1903.

Leclerc, L. Histoire de la médecine arabe. Paris: E. Leroux,1876; Rpt. Rabat: Ministère des habous et des affairesislamiques, Royaume de Maroc, 1980 and New York:B. Franklin, 1960.

Sarton, George. Introduction to the History of Science.Baltimore: Williams & Wilkins, 1927.

Schact, J. Ibn But.lān. Encyclopedia of Islam. Leiden: Brill,1960.

Schact, J. and M. Meyerhof. The Medico-PhilosophicalControversy between Ibn But.lān of Baghdad and IbnRid.wān of Cairo. Cairo: Egyptian University Faculty ofArts, 1937.

Usāma ibn Munqidh. Kitāb al-I i˓bar. Al-Qāhirah: Maktabatal-Thaqāfah al-Dīnīyah, 1980.

Ibn H. awqal

EMILIA CALVO

Ibn H. awqal al-Nasibī Abū’l-Qāsim Muh.ammad ibn ˓Alīwas born in Nisibis (now Nusaybin, Turkey) in thesecond half of the tenth century. Heworked as amerchantand traveled, beginning in AD 943, through the Muslimworld, visiting the Maghreb and Andalusia between 947and 951; Egypt, Armenia, and Azerbaijan around AD955; Iraq, Persia, Transoxiana, and Khwarazm between961 and 969. In AD 973, he was in Sicily.

1104 Ibn Hubal

Ibn H. awqal is the author of a book on geographyentitled Kitāb al-masālik wa’l-mamālik (Book on theRoutes and Kingdoms), also known as Kitāb s.ūratal- a˓rd. , which belongs to the category of the so-calledAtlas of Islam. It consists of a description of the Islamiccountries, although some non-Islamic regions of Sudan,Turkey, Nubia, and Sicily are also described.

Ibn H. awqal based his work on al-Is.t.akhrī’s book andincorporated new material from his travels which ledto three successive revisions of his Kitāb al-masālik:the first one in AD 967, dedicated to Sayf al-Dawla;the second ca. AD 977, and the third ca. 988. The finalresult was a book whose descriptive part surpassed theworks of earlier authors.

From the contents of his work, his sympathy with theFāt.imid movement can be deduced. He showed acertain interest toward Fāt.imid politics, although hecannot be considered a Fāt.imid dā ī˓ (propagandist). Healso gives economic information. His interests arefocused not on rare or precious goods but on basicagricultural and artisanal products.

Ibn H. awqal’s Kitāb al-masālik influenced the workof later geographers such as Abū’l-Fidā. He is also theauthor of a book on Sicily which is not preserved.

See also: ▶Balkhī School, ▶Geography

References

Ibn H. awqal. Bibliotheca Geographorum Artabicorum. Kitābal-masālik wa’l-mamālik. Ed. M. J. de Goeje. Vol. 2.Leiden: Brill, 1873.

---. Bibliotheca Geographorum Artabicorum. Kitāb s.ūratal- a˓rd. . Ed. J. H. Kramers. 2nd ed. Vol. 2. Leiden: Brill,1938 (Rpt. 1967).

Miquel, André. La géographie humaine du monde musul-mane jusqu’au milieu du XIe siècle. Paris: Mouton, 1967.

---. Ibn H. awkal. Encyclopédie de l’Islam. 2nd ed. Vol. 3.Leiden/Paris: E. J. Brill/G. P. Maisonneuve, 1971. 810–1.

Vernet, Juan. Ibn H. awqal. Dictionary of Scientific Biography.Vol. 6. New York: Charles Scribner’s Sons, 1972. 186.

Wiet, G. Configuration de la Terre. Paris: CommissionInternationale pour la Traduction des Chefs d’oeuvres,1964.

Ibn Hubal

E. RUTH HARVEY

Muhadhdhib al-DīnAbū’l-H. asan A˓lī ibnAh.mad ibn Ā˓liibn Hubal al-Baghdādī was a famous physician, medicalauthority, and accomplished poet. Born in Baghdad in1121 (AH 515), he migrated to Khilat (modern Ahlat, onthe shore of Lake Van, Turkey), and became very

prosperous in the service of the local ruler. He latermoved toMardin to serve another lord, and died atMosul(in modern Iraq) in 1213 (AH 610). His chief work,Kitābal-Mukhtār f ī al-T. ibb (The Choice Book of Medicine),was written in about 1165. It resembles the medicalencyclopedias of Ibn Sīnā and al-Rāzī in that it is acompendium of Galenic medical knowledge, supplemen-ted by personal clinical practice. The Choice Book isdivided into three main parts, comprising anatomy andgeneral principles, a pharmacopoeia, and a list ofmaladiesarranged according to the affected organs, running fromhead to foot. Although this large book does not seemto have been translated into Latin during the MiddleAges, the number, diffusion, and varying ages of themanuscript copies attest to its popularity. No copy appearsto survive of Ibn Hubal’s Kitāb al-T. ibb al-Jamāli (Bookof Medicine for Jamal al-Din al-Wazir). A short workon logic, al-Ārā˒wa’l-mushāwarāt, in manuscript in Paris(B.N. MS 2348) is ascribed to him.

The manuscripts of The Choice Book in Leiden,Paris, Cairo, and India are listed in Brockelmann; thereare also several copies in Turkey, and fragmentary onesin Princeton and the British Library in London (theLondon text starts with the diseases of the brain). Thewhole Arabic text was edited in Hyderabad 1943–1944,but Albert Dietrich maintains that a proper criticaledition is still badly needed. Two chapters of Ibn Hubal’smedical encyclopedia were published from the Leydenmanuscript with an accompanying French translation;they describe the causes, symptoms, and treatment ofstones in the kidneys and bladder. Ibn Hubal employsthe usual medieval medical terminology derived fromearlier Greek physicians: four fluids, or humors, withinthe body (blood, phlegm, choler (yellow bile), andmelancholy (black bile)) are held to constitute in theirbalance and proportions the essential foundations ofgood health; pain and disease reveal an evil conditionor imbalance among the fluids. Most remedies andtreatments consist of trying to correct the malfunction-ing fluid through diet, bleeding, or alteration of thepatient’s physical surroundings. In spite of what wemight today consider the erroneous basis of his theoret-ical approach, Ibn Hubal shows an impressive concernfor personal observations and clearly relies on extensiveclinical practice. In discussing stones, for instance, heattributes the condition to excessive bodily heat whichcauses phlegm, a “thick fluid,” to form deposits in thekidneys and bladder. He prescribes medicines such ashorseradish, ginger, and chicken soup to break up thestones or cause them to be passed. He also cites his ownpersonal experience of a more desperate remedy whichhe witnessed: a surgical operation to remove a bladderstone from a boy. He cites al-Rāzī and Rufus of Ephesus,but conveys the impression of a knowledgeable practicalphysician, mindful of the agonizing pain caused by thecondition he is discussing.

Ibn Juljul 1105

References

Dietrich, Albert. Medicinalia Arabica. Göttingen: Vanden-hoeck u. Reprecht, 1966.

Ibn Abī Us.aybi a˒h. ˓Uyūn al-Anbā f ī t.abaqāt al-at.ibbā .˓Beirut: Dār Maktabat al-H. ayāh, 1965. 471–2.

Ibn Hubal. Traitésur le calcul dans les reins et dans la vessie.Ed. P. De Koning. Leiden: E. J. Brill, 1896.

---. al-Mukhtār f ī al-T. ibb. 4 vols. Hyderabad: Da’irat al-Ma‘arif al-‘Uthmaniyah, 1943–1944.

Vernet, J. Ibn Hubal. The Encyclopaedia of Islam. New ed.Vol. 3. Leiden: Brill, 1968–1971. 802.

Ibn Ish. aq Al-Tunisı

I

JULIO SAMSÓ

Abū-l-˓Abbās Ah.mad ibn ˓Alī ibn Ish.āq al-Tamīmī al-Tūnisī was a Tunisian astronomer of the early thirteenthcentury. He compiled an impressive astronomical hand-book with tables (zīj) a manuscript of which (copied ca.1400) was discovered by David A. King. It contains animportant set of tables (completed ca. 1218) which markthe starting point of a Maghribian (North Africa) astro-nomical school. Parts of these tables seem original andare based, according to the famous historian IbnKhaldūn,on observations made by a Sicilian Jew. The rest is amiscellaneous collection of materials which derive fromAndalusian sources, many of which seem lost, by Ibnal-Zarqāllu (d. 1100), Ibn Mu ā˓dh al-Jayyānī (d. 1093),Ibn al-Kammād (fl. ca. 1125), Ibn al-Hā i˒m (fl. ca. 1204)as well as others. The canons (instructions for the useof the numerical tables) were not written by Ibn Ish.āqbut by some later author who also used materials derivedfrom the aforementioned Andalusian zījes. Ibn Ish.āq’szīj is, therefore, a first rate new source for the study ofboth Andalusian and Maghribian astronomy.

References

Kennedy, E. S. and David A. King. Indian Astronomy inFourteenth Century Fez: The Versified Zīj of al-Qusunt.īnī.Journal for the History of Arabic Science 6 (1982): 3–45.Rpt. King, D. A. Islamic Mathematical Astronomy.London: Variorum Reprints, 1986.

King, David A. An Overview of the Sources for the Historyof Astronomy in the Medieval Maghrib. DeuxièmeColloque Maghrebin sur l’Histoire des MathématiquesArabes. Tunis: Université de Tunis, 1988. 125–57.

Samsó, Julio and Honorino Mielgo. Ibn Ish.āq al-Tūnisī andIbn Mu ā˓dh al-Jayyānī on the Qibla. Ed. J. Samsó. IslamicAstronomy and Medieval Spain. Aldershot: VariorumReprints, 1994 (no. VI).

Samsó, Julio and Eduardo Millás. Ibn al-Bannā ,˒ Ibn Ish.āqand Ibn al-Zarqālluh’s Solar Theory. Islamic Astronomyand Medieval Spain. Ed. J. Samsó. Aldershot: VariorumReprints, 1994 (no. X).

Ibn Juljul

EMILIA CALVO

Ibn Juljul al-Andalusī, Sulaymān ibn H. asan, was bornin Córdoba in AD 943 and died ca. 994. He studiedmedicine with a group of Hellenists presided over byH. asdāy ibn Shaprūt., a Jewish physician and vizier ofthe Caliph ˓Abd al-Rah.mān III, and later became thepersonal physician of Caliph Hishām II (976–1009).Ibn Juljul is the author of T. abaqāt al-at.ibbā˒ wa

‘l-h. ukamā˒ (Generations of Physicians and Wise Men),the oldest extant summary in Arabic on the history ofmedicine (it was finished in AD 987), after Ish.āq ibnH. unayn’s Ta r˒īj al-at.ibbā˒ (History of the Physicians).It contains 57 biographies grouped into nine genera-tions. Thirty-one of them concern Asian authors, andthe rest refer to African and Andalusian scholars.Ibn Juljul used Eastern sources (Hippocrates, Galen,

Dioscorides) and Western ones (Orosius, Isidore) andestablished the chronological limits of the Latin influ-ence on medicine in Andalusia. The work has chrono-logical errors but provides interesting information aboutthe oldest translations into Arabic, in the time of theCaliph ˓Umar II (AD 717–719).Other works of Ibn Juljul are Tafsīr asmā˒ al-adwiya

al-mufrada min kitāb Diyusqūridūs (Explanation ofthe Names of the Simple Drugs from Dioscorides’Book), written in 982, from which only a fragment ispreserved, containing the transcription of the Greeknames of 317 simple medicines, their translation intoArabic and their identification; Maqāla fī dhikr al-adwiya al-mufrada lam yadhkurhaDiyusqūridūs (Trea-tise on the Simples not Mentioned by Dioscorides),which includes 62 simple medicines not mentioned inDioscorides’ Materia Medica; Maqāla fī adwiyat al-tiryāq describing the components of the theriaca; andRisālat al-tabyīn fī-mā ghalat.a fīhi ba d˓. al-mutat.abbibīn(Treatise on the Explanation of the Errors of SomePhysicians).

References

Dietrich, A. Ibn Djuldjul. Encyclopédie de l’Islam. 2nd ed.Vol. III. Leiden/Paris: E. J. Brill/G. P. Maisonneuve, 1971.778–9.

Garijo, Ildefonso. El tratado de Ibn Ŷulŷul sobre losmedicamentos que no mencionó Dioscórides. Cienciasde la Naturaleza en Andalusia. Textos y Estudios I.Ed. Expiración García Sànchez. Granada: ConsejoSuperior de Investigaciones Científicas, 1990. 57–70.

Ibn Juljul. Kitāb t.abaqāt al-at.ibbā˒ wa ‘l-h. ukamā .˒ Ed.F. Sayyid. Cairo: Mat.ba a˓t al-Ma h˓ad al-Ilmī al-Faransīlil-Āthār al-Sharqīyah, 1955.

---. Ibn Ŷulŷul, Tratado Octavo. Ed. and Spanish Trans.Ildefonso Garijo. Córdoba: Universidad de Córdoba, 1992a.

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---. Ibn Ŷulŷul, Tratado Sobre los Medicamentos de la Tríaca.Ed. and Spanish Trans. Ildefonso Garijo. Córdoba:Universidad de Córdoba, 1992b.

Johnstone, P. Ibn Juljul: Physician and Herbalist. IslamicCulture 73 (1999): 37–43.

Samsó, Julio. Las Ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992.

Vernet, Juan. Los médicos andaluces en el “Libro de lasgeneraciones de los médicos” de Ibn Ŷulŷul. Anuario deEstudios Medievales 5 (1968): 445–62; Rpt. in Estudios deHistoria de la Ciencia Medieval. Barcelona: Universidadde Barcelona, 1979. 469–86.

---. Ibn Juljul. Dictionary of Scientific Biography. Vol. 7.New York: Charles Scribner’s Sons, 1973. 187–8.

Ibn Jumay˒

HARTMUT FAHNDRICH

A contemporary of the great Jewish doctor andphilosopher Moses Maimonides, Ibn Jumay ,˒ was oneof the physicians in the service of S.alāh ad-Dīn. He wasborn of a Jewish family in Fustat (Egypt) and studiedwith another physician of some renown, ˓Ādnān ibnal-˓Aynzarbī (d. 548/1153). The relevant biographicaldictionaries mention Ibn Jumay ’˒s talents in medicineas well as his highly developed linguistic conscious-ness, inducing him always to carry al-Jawharī’s Kitābas.-s.ah. āh. (The Truthful Guide) to class so he couldcheck words of which he was uncertain. Ibn Jumay˒died in 594/1198.

In Ibn Abī Us.aybi a˒’s dictionary of medical doctors,˓Uyūn al-anbā˒ fī t.abaqāt al-at.ibbā˒ (Sources ofInformation About the Classes of Physicians), IbnJumay˒ is presented as the author of eight works onmedical or medicine-related subjects, the most impor-tant of them being Kitāb al-irshād li-mas.ālih. an-nufūswa ’l-ajsād (Guide to the Welfare of Souls and Bodies),a compendium of the different fields of the art ofmedicine. Others also deal with practical questions ofthe doctor’s craft such as first aid or nutritive advice.

The only one of Ibn Jumay ’˒s works published todate, al-Maqāla as.-s.alāh. īya fī ih.yā as.-s.ināa at.-t.ibbīya(Treatise to S.alāh. ad-Dīn/Saladin on the Revival of theArt of Medicine), is not mentioned by Ibn AbīUs.aybi a˒.It is a deontological work, i.e., it deals with the doctor’sprofession on a more theoretical level.

This treatise, as Ibn Jumay˒ mentions in theintroduction, owes its composition to a conversationhe had with his sovereign on the deplorable state ofmedicine in his time, the reasons for this, and waysto ameliorate the situation. Thus, formally the workstands in the literary tradition of the epistle, a genre

frequently employed by Ibn Jumay˒ in other works andby Arabic medical authors in general. Its contents – thecomplaints about the declining state of the art andconsiderations about its improvement – were notunknown in his time either. The theme goes back toGalen or even Hippocrates.

The treatise falls into three chapters: Chapter 1concerns the presentation of medicine, including thequalities of medicine and the need for it, as well as thedifficulties ofmedicineand their consequences;Chapter2deals with the reasons for the decline of medicine,including a brief presentation of its history; andChapter 3suggests ways to revive the art of medicine.

Whereas compendia of a more technical presentationof medicine in medieval Arabic literature are compara-tively numerous, the same cannot be said about thiskind of work, with its introductory and deontologicalcharacter. In that lies the importance of this doctor ofthe twelfth century AD, Ibn Jumay .˒

See also: ▶Moses Maimonides, ▶Medicine in Islam

References

Fenton, Paul B. The State of Arabic Medicine at the Time ofMaimonides According to Ibn Ĝumay ’˒s Treatise on theRevival of the Art of Medicine. Moses Maimonides –Physician, Scientist, and Philosopher. Ed. Fred Rosner andSamuel S. Kottek. Northvale, New Jersey: Jason Aronson,1993. 215–29, 270f.

Jumay .˒ Ibn Treatise to S.alāh. ad-Dīn on the Revival of the Artof Medicine. Ed. and trans. Hartmut Fähndrich. Wiesba-den: Kommissionsverlag Franz Steiner, 1983.

Meyerhof, Max. Sultan Saladin’s Physician on the Transmis-sion of Greek Medicine to the Arabs. Bulletin of theHistory of Medicine 18 (1945): 169–78.

Ullmann, Manfred. Die Medizin im Islam. Leiden: Brill,1970.

Ibn Khaldun

CHARLES E. BUTTERWORTH

˓Abd al-Rah.mān ibn Khaldūn (1332/732–1406/808)spent the first two-thirds of his life in North Africa andMuslim Spain, fleeing in 1382/784 to Egypt, where heremained until his death. Though he is best known forthe lengthy Introduction (Muqaddima) to his massivephilosophical history of civilization (Kitāb al- I˓bar),Ibn Khaldūn spent much of his life in politicalactivities. Born and raised in Tunis, he read the Qur’ānand studied the religious sciences as well as Arabic and

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poetry, then was educated in logic, mathematics,natural science, and metaphysics. He also receivedspecialized training in court correspondence and admin-istrative matters, subjects that allowed him to become acourt secretary to the Marinid ruler Abū I˓nān in Fez atabout the age of 22.

After some vicissitudes, including almost 2 years ofprison, Ibn Khaldūn went to Grenada in 1362 tobecome an advisor and tutor to Muh.ammad V. Thatposition lasted only about 2 years, no longer than hissubsequent position as prime minister or h.ājib to PrinceAbū ˓Abd Allāh of Bougie. Following these forays intopractical politics, Ibn Khaldūn endured several yearsof upheaval (1366/766–1375/776), settled for about4 years in Qal a˓t Ibn Salāma near Oran and began workon his history, then moved to Tunis under the patronageof Abū al-˓Abbās in order to have access to documentsand libraries. After a few years there, court intrigues ledhim to seek tranquility in Egypt.

During the next quarter of a century he servedthe Mamlūk Sult.ān Barqūq as judge (qād. ī) and chiefjudge (qād. ī al-qud.ā), professor at various universities(including the prestigious al-Azhar), and one timeuniversity president. A few years before his death hemet with the famous Mongol chieftain Tamerlane. Butthe period in Egypt was, above all, a time for revisinghis Kitāb al- I˓bar and working on the Introduction(Muqaddima) to it.

The Kitāb al- I˓bar is a multivolume effort that, in hiswords, sets forth “the record of the beginning andthe suite of the days of the Arabs, Persians, Berbers,and the most powerful of their contemporaries.” ItsIntroduction consists of six very long chapters thatexplore the character of human civilization in generaland Bedouin civilization in particular, as well as thebasic kinds of political associations, and then thecharacteristics of settled civilization, the arts and craftsby which humans gain their livelihoods, and, finally,the different human sciences. Ibn Khaldūn starts byexplaining the merit of history and how to go aboutwriting it. Properly speaking, the reason to write historyor the “inner meaning of history” is, by means ofreflection, to get “at the truth, subtle explanation of thecauses and origins of existing things, and deepknowledge of the how and why of events.” Though hisenterprise is therefore “rooted in philosophy” and to beconsidered a branch of it, Ibn Khaldūn acknowledges aproblem with the way history has come down. Manyunqualified people have trammeled with the books ofhistory written by competent Muslim historians; theyhave introduced tales of gossip imagined by themselvesas well as false reports. Moreover, other historians havecompiled partial reports of particular dynasties andevents without looking to the way things have changedover time, without looking at natural conditions and

human customs. Consequently, Ibn Khaldūn considershis task to be that of showing themerit of writing history,investigating the various ways it has been done, andshowing the errors of previous historians.What needs tobe known, and thus what he sets out to make known, are“the principles of politics, the nature of existent things,and the differences among nations, places and periodswith regard to ways of life, character, qualities, customs,sects, schools, and everything else… plus a comprehen-sive knowledge of present conditions in all theserespects… complete knowledge of the reasons for everyhappening and… [acquaintance] with the origin of everyevent.” Yet in the end Ibn Khaldūn hints that he hasalmost digressed in the whole undertaking. What hewanted to dowas to explain the nature of civilization andits accompanying accidents, but he fears he has strayedfrom his basic point.

References

Ibn Khaldūn. The Muqaddimah: An Introduction to History.Trans. Franz Rosenthal. New York: Pantheon Books, 1958.

Mahdi, Muhsin. Ibn Khaldūn’s Philosophy of History.London: George Allen and Unwin, 1957.

Ibn Khurdadhbih

SAYYID MAQBUL AHMAD

Abu l˒-Qāsim ˓Ubayd Allāh ibn Khurdādhbih (alsospelled Ibn Khurradādhbih), the first scholar to writeon world geography in Arabic, was born in ca. AH 205/AD 820 (or AH 211/AD 825), and died in ca. AH 300/AD 912. Probably born in Khurāsān, he was broughtup in Baghdad. His grandfather, Khurdādhbih, was aZoroastrian, latter converted to Islam, and his fatherwas the governor of T. abaristān. When he grew up, hebecame the director of posts and information in Jibāl(Media) and subsequently became director-general ofthe same department in Baghdad and later in Sāmarrā(Iraq). He became a companion of the ˓Abbāsid Caliphal-Mu t˓amid (AH 256–279/AD 870–892).Ibn Khurdādhbih was a versatile writer; besides

writing on geography, he wrote on history, genealogy,music, wines, and even on the culinary art. Al-Nadīm,in his al-Fihrist, lists at least eight works to his credit.The Arab historian Abu l˒-H. asan ˓Alī ibn al-H. usaynal-Mas ū˓dī (d. AD 956) considered him an imām(leader) in authorship and mentions his voluminoushistorical work dealing with the ancient kings and

1108 Ibn Mājid

peoples of Iran (Murūj 1965). Ibn Khurdādhbih alsoclaimed to have translated into Arabic the geographicaltreatise of Claudius Ptolemy (ca. AD 90–168) from a“foreign language” (probably Syriac or Greek), but thetranslation is not extant.

However, Ibn Khurdādhbih’s major work on geog-raphy, entitled Al-Masālik al-Mamālik (Roads andKingdoms), was published by M. J. De Goeje in1889. In fact, this work is an abridgement (preparednot later than AD 885–886) of his larger work (notextant) written in ca. AD 846–847. Considering thevast amount of information contained in the work andthe early date of its compilation, it may be said that IbnKhurdādhbih was the father of Arab-Islamic geogra-phy; no work of such magnitude existed before him.Al-Masālik al-Mamālik deals briefly with mathematicaland physical geography, but the major portion of thework is devoted to descriptions of land and sea routesin the four directions emerging from al-Sawād. Then, itdeals with marvels of the world, seas and mountains,sources of the rivers, and reports on countries like Indiaand Central Asia.

It is not unlikely that Ibn Khurdādhbih relied heavilyfor his information on the ancient Sassanian govern-ment records which must have become available tohim as the person in charge of the department ofposts and information in Baghdad and elsewhere.Again, in his methodology and arrangement of thematerial and in the use of geographical terms andPersian couplets, a distinct Persian influence is discern-ible. The ancient Persians used to divide the knownworld into seven circular regions called kishvars(kingdoms) with Irānshahr at the center and theremaining six circles drawn around it. Such an arrange-ment is observable in his descriptions of the variousroutes emerging from al-Sawād, which, he says, wascalled dil-i Irānshahr (the heart of Iraq).

Ibn Khurdādhbih was not only the first to write ongeography in Arabic, but he also set the style forwriting on descriptive geography. Several later Arab-Islamic geographers utilized his work as a major sourceof information.

See also: ▶Geography in Islam

References

Ahmad, S. Maqbul. Djughrāfiyā. Encyclopedia of Islam.Leiden: Brill, 1960.

---. Arabic Classical Accounts of India and China. Shimla:Indian Institute of Advanced Study, 1989.

Al-Mas ū˓dī. Murūj al-Dhahab wa Ma ā˓din al-Jawhar(Meadows of Gold and Mines of Gems). Trans. AloysSprenger. London: Allen, 1841.

Ibn Khurdādhbih. Al-Masālik al-Mamālik. Ed. M. J. DeGoeje. Leiden: E. J. Brill, 1889.

Krachkovskii, I. IU. IstoriaArabskoiGeograficeskoiLiteratury.Moscow and Leningrad, 1957. (S.ālāh. al-Dīn U˓thmanHāshim, Arabic Trans. Tārīkh al-adab al-jughrāf ī al-A˓rabī.Vol. 1. Beirut: Dār al-Gharb al-Lubnān, 1987.)

Ibn Majid

SAYYID MAQBUL AHMAD

Shihāb al-Dīn Ah.mad ibn Mājid ibn Muh.ammad ibnAmr ibn Fad. l ibn Duwayk ibn Yūsuf ibn H. asan ibnH. usayn ibn Abī Ma l˓aq al-Sa d˓ī ibn Abu’l-Rakā i˒b al-Najdī was the greatest Arab navigator of the fifteenthcentury AD and one of the greatest of the Middle Ages.We do not know the date of his birth or death, but hemust have died at an advanced age sometime in the firstdecade of the sixteenth century. Born in Julfār (Oman),he belonged to an illustrious family of navigators. Bothhis father and grandfather were mu a˓llims (masters ofnavigation) of repute.

Ibn Mājid wrote a number of works, both in proseand poetry, on nautical theory and on describingthe seas (mainly the Indian Ocean) which served asguides for the Arab navigators of later periods. Amonghis important works in prose is the Kitāb al-fawā i˒df ī u˓s.ūl i˓lm al-bah. rwa’l-qawā i˓d (TheBookofBenefitson the Principles of the Science of Navigation), datedAH 895/AD 1489–1490. This book and many othershave been reproduced in the editions mentioned in thebibliography.

Ibn Mājid considered himself the fourth of the greatArab navigators of the Middle Ages; the other threewere Muh.ammad ibn Shādān, Sahl ibn Abān, and Layt.ibn Kahlān, who belonged to the Abbāsid period. Hethought his own works were more accurate than theirs,since they were more current and since many of theports mentioned in the older works no longer existed.Apart from his practical experiences as a navigator, hehad studied and improved upon the work of his father(al-H. ijāzīya) and had studied a number of earlierArabic works on astronomy and geography.

On the practical side of navigation, it is not unlikelythat Ibn Mājid was in contact with the Indian navigatorsof his time, the S.ūliyān (Cholas of Tamil Nadu, India)and with the Gujarati and the Konkani (Maharashtra,India) navigators, whose qiyāsāt (readings of the portsand harbors) he seems to have known. He was particu-larly knowledgeable about Siam and Bengal, and thesenavigators frequented these regions more than the Arabnavigators did.

In his works Ibn Mājid covered a number of subjectsrelating to navigation, nautical astronomy, oceanography,and geography. In his Kitāb al-fawā i˒d, he pays special

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attention to subjects of a more general nature, likeguidelines to navigators such as the prerequisites forsailing on the sea, and he describes the lunar mansions,the stars corresponding to the 32 divisions (aqnān) of thecompass card, the winds and seasons of the seas, nauticalinstruments, and the essentials required by captains ofboats. These include knowledge of the rising and corre-sponding settings of the stars (al-anwā˒), latitudes andlongitudes, landfalls, and tides.Heemphasizes that beforesailing, captains should see that their instruments are inperfect order, the sailors obedient, and the seasonssuitable. They should be patient and soft-spoken, shouldnot deprive merchants of their rights, and they should becourageous, literate, andwell behaved.He also presents asystematic description of the sea coasts of the Oikumene(the known world at that time), which no geographer haddone before. From his writings, it appears that he did notconceive that a terra incognita existed in the southernquarter of the earth, as other geographers of his timebelieved.He thought that the IndianOceanwasconnectedwith the Atlantic through a sea channel, which he callsal-madqal (place of entry).

Ibn Mājid claimed to have made several contribu-tions to navigation and to determining the direction ofthe qibla (Mecca) from different positions of the earthwith the help of the compass card. He also claimed tohave fixed a magnetized needle on the mariners’compass (probably on a day box). Ibn Mājid had metVasco da Gama, and had guided him to Calicut, India.Although the Portuguese sources do not mention himby name in this regard, we know from an Arabic work,al-Barq al-Yamānī f ī’l-fath. al-˓Ut.mānī (The YemeniteLightning on the Ottoman Conquest) by al-Nahrawālīthat it was he who directed Vasco da Gama fromMalindi (East Africa) to India.

See also: ▶Qibla, ▶Lunar Mansions, ▶Compass

References

Ahmad, S. Maqbul. Ibn Mājid. Encyclopaedia of Islam.Leiden: E. J. Brill, 1960. 856–69.

---. Ibn Mājid. A History of Arab-Islamic Geography 9th–16th Century AD. Ed. Sayyid Maqbul Ahmad. Amman: Alal-Bayt University, 1995.

Ferrand, Gabriel. Instructions nautiques et routiers arabeet portugais des XVe et XVIe siècles. Paris: Geuthner, 1921.

Khūrī, Ibrāhīm and I˓zzat H. asan. Kitāb al-fawā i˒d f ī u˓s.ūli˓lm al-bah. r wa’l-qawā i˓d. Damascus: al-Mat.ba a˓h al-Ta ā˓wunīyah, 1390/1971.

Shumovsky, T. A. T. alāt.a rahmānajāt al-majhūla li Ah.mad b.Mājid. Moscow: Nauka, 1957.

Tibbetts, Gerald R. Arab Navigation in the Indian OceanBefore the Coming of the Portuguese; Being a Translationof Kitāb al-Fawā i˒d f ī sūl al-bah. r wa’l-qawā i˒d of Ah.madb. Mājid al-Najdī. London: Royal Asiatic Society of GreatBritain and Ireland, 1971.

Ibn Masawayh

DANIELLE JACQUART

Abū Zakariyyā˒ Yūh.annā ibn Māsawayh was born inBaghdad during the caliphate of Hārūn ar-Rashid(786–809), and not in 777 as was stated by Leo theAfrican. His father, Māsawayh, was a pharmacist in theservice of the physician Jibrā˒īl ibnBah. tishū ,˓ withwhomhe came from Jundīshāpūr (in Persia) to Baghdad. Hismother was a slave, named Risala, whom Māsawayhbought from the physician Dawūd ibn Sarābiyūn. Thus,Yūh.annā ibn Māsawayh belonged to the milieu ofChristian Nestorian physicians, who played an importantpart during the eighth and ninth centuries. He marriedthe daughter of his colleague Abdallāh at-Tayfūrī andhad a son of poor intelligence. He was very famous as ateacher and practitioner; he became the personal phy-sician of four successive caliphs from al-Ma˒mūn toal-Mutawakkil. He died in Samarra in 857.As for many other authors of this period, it is difficult

to distinguish legend and history in his biography. It wassaid that he did translations from Greek into Arabic, butnone is extant under his name; most probably, he onlycommissioned some of them. For instance, it is wellattested that H. unayn ibn Ish.āq undertook the transla-tion of Galen’s Methodus medendi (Arabic Kitāb hīlatal-bur ;˒MethodsofHealing) at IbnMāsawayh’s request.The relationship between both physicians was never-theless strained, at least at the beginning: IbnMāsawayhis supposed to have driven H. unayn out of his teachingposition, who thenwent traveling in order to learn Greekand purchasemanuscripts. It was also reported byArabicmedieval historians that Ibn Māsawayh had the opportu-nity of dissecting an ape, which had been given tothe caliph by the prince of Nubia in 836 as a present.Following in Galen’s footsteps Ibn Māsawayh afterwardwrote an anatomical monograph, which can perhaps beidentified with his Kitāb at-tashrīh. (Book of Anatomy).Apart from his knowledge of Greek medicine, IbnMāsawayh had access to some Indian works: he quotes,for instance, Āryabhat.a in his ophthalmological treatiseKitāb dafal al- a˓in (Book on the Defectiveness ofthe Eye).Ibn Abī Us.aybi a˓ listed 42 works; some others were

quoted by al-Rāzī and al-Bīrūnī. But only 31 are extant,as far as we know, and very few have been edited orstudied. Those that have been edited – and sometimestranslated into English or French – are the Aphorisms,the works on barley water, simple drugs, and perfumes,as well as the medical calendar; the ophthalmologicaltreatises have also been analyzed. It seems that amongthe works which were translated into Latin during theMiddle Ages under the names of “Mesuë” or “Johannes

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Damascenus,” only the Aphorismi Johannis Damasceniand some ophthalmological fragments can be attributedto Ibn Māsawayh; the other ones, mainly pharmacolog-ical, are probably apocryphal for the most part. TheAphorismi – a faithful translation of Nawādir at.-t.ibb –were largely diffused from the twelfth century; a secondtranslation appeared as the sixth book of Rāzī’s SecretsofMedicine: it was done during the thirteenth century bythe Dominican Giles of Santarem.

Some original features of Ibn Māsawayh’s medicinecan be drawn from his Nawādir at.-t.ibb. Dedicated toH. unayn ibn Ish.āq and modeled on the HippocraticAphorisms, this short work was intended to givepractical advice. The eight first aphorisms canbe consid-ered as a kind of commentary on the first Hippocraticaphorism: “Life is short, art long, opportunity fleeting,experiment dangerous, judgment difficult.” Theystressed the necessity for physicians to be both learnedand skilled. Throughout the remaining 124 aphorismsthe following topics are covered: the link between bodyand soul, the observance of astrological and climatolog-ical rules, the attention that physicians have to pay to thehealthy nature of their patients, the numerical ratioswhich rule human temperaments, as well as naturalsubstances used for treatment. It has to be noted that thislast idea was deeply developed by Ibn Māsawayh’scontemporary, al-Kindī. Ibn Māsawayh seems also tohave been verymuch attached to the idea that physiciansmustmainly reinforce nature by using drugs similar to it;medical treatment with substances contrary to diseasehad to be prescribed cautiously and their sole goal was topurge. Physicians had to be cautious not to alter naturetoo much. For example, Ibn Māsawayh stated: “It isimportant that, against diseases, the strongest contrary isnot introduced into the body, since this would be veryharmful; it can be compared with a very cold windwhich, during the same day, blows after a very hot one”(aph. 60). In the same manner, treatment by diet waspreferred to pharmacopoeia: “If the physician can treatwith food, to the exclusion of drugs, he will be verysuccessful” (aph. 108). In addition to several pharmaco-logical treatises, Ibn Māsawayh composed an importantwork on dietetics.

Ibn Māsawayh’s works remain very little known,despite their importance in the history of Arabicmedicine. Detailed studies would shed light on thedecisive stage constituted by the beginning of the ninthcentury, before the spread of H. unayn’s translations.

See also: ▶al-Kindī, ▶Leo the African

References

Hamarneh, Sami K. Ibn Masawayh (Mesuë the Elder): OnMedicine, Therapy and Pathology. Hamdard medicus 40.1(1997): 5–16.

Ibn Māsawayh, Yūh.annā. Le livre des axiomes médicaux. Ed.Danielle Jacquart, Gérard Troupeau. Genève/Paris: Droz/Champion, 1980.

Levey, Martin. Ibn Māsawaih and His Treatise on SimpleAromatic Substances. Journal of the History of Medicine16 (1961): 394–410.

Prüfer, Carl and Max Meyerhof. Die Augenheilkunde desJūh.annā b. Māsawaih. Der Islam 6 (1916): 217–56.

Sbath, Paul. Le livre des temps d’ Ibn Massawaih. Bulletin del'Institut d'Egypte 15 (1933): 235–57.

---. Traité sur les substances simples aromatiques parYohanna ben Massawaih. Bulletin de l'Institut d'Egypte19 (1937): 5–27.

---. Le livre sur l'eau d'orge de Youhanna ben Massawaih.Bulletin de l'Institut d'Egypte 21 (1939): 13–24.

Sezgin, Fuat. Geschichte des arabischen Schrifttums. Vol. III.Leiden: Brill, 1970. 231–6.

Sournia, Jean-Charles and Gérard Troupeau. Médecine arabe:biographes critiques de Jean Mésué (VIIIe siècle) et duprétendu Mésué le Jeune’ (Xe siècle). Clio Medica 3(1968): 109–17.

Troupeau, Gérard. Les Aphorismes De Jean Mésué, médecinDuCalifeHarounAl-Rashid, Et LeurDiffusionEnOccident.Histoire des sciences médicales 3 (1997): 317–26.

Ullmann, Manfred. Die Medizin im Islam. Leiden: Brill,1970.

Ibn Mu a˓dh

A. MARK SMITH

Ibn Mu ā˓dh al-Jayyānī, Abū ˓Abd Allāh Muh.ammad(d. ca. 1093) has traditionally been assigned a birth dateof 989. However, recent scholarship suggests that IbnMu ā˓dh was born somewhat later, in the early eleventhcentury. The only secure date we have for him is 1079,the year of a solar eclipse he describes from first-handobservation. The ending “al-Jayyānī” to his nameindicates that he was from Jaén in Andalusia, where heevidently served as a qād. ī (judge) for much of his life.Among his few surviving astronomical and mathe-matical works are included the Tabulae Jahen, a set ofastronomical tables based on those of al-Khwārizmīand probably translated into Latin by Gerard ofCremona; Maqāla fi sharh. al nisba (On Ratio), acommentary on Book 5 of Euclid’s Elements; andKitāb majhūlāt qisiyy al-kura (Determinations of theMagnitudes of the Arcs on the Surface of a Sphere),a work on trigonometry. Certainly the most original,and perhaps the most historically significant of hisextant works, is the brief treatise On Twilight and theRising of Clouds.

While no Arabic exemplar has yet come to light (theoriginal title was probably Ma’l-fajr wa’l-shafaq), thiswork has nonetheless reached us in three other linguistic

Ibn Mun i˓m 1111

I

forms: a fourteenth-century Hebrew translation from theArabic (represented by one manuscript), a late twelfth-century Latin translation from the Arabic, probably byGerard of Cremona (represented by 25manuscripts), anda fourteenth-century Italian translation from the Latin(represented by one manuscript). The sheer number ofLatinmanuscripts–plus the Italian translation– indicatesthe seriousness with which this treatise was receivedand disseminated in the medieval West. That it wascommonly misattributed to Ibn al-Haytham, author ofthe magisterial Kitāb al-manāz.ir (De aspectibus), mayhave had something to do with this. There is also clear,albeit indirect, evidence thatOn Twilight exerted its shareof influence in the medieval East as well.

Ibn Mu ā˓dh’s purpose in On Twilight is to determinethe height of the atmosphere under the assumption thatthe first light of dawn is produced when rays from therising sun tinge vapors at the very upper edge of theatmosphere. Although he offers no practical justifica-tion for this inquiry, he does, in a couple of querulousasides, berate those (religious conservatives?) whowould squelch rational inquiry out of mere ignorance.The determination itself depends upon four basic para-meters: the depression of the sun below the horizonat first light (18°); the mean distance between earth andsun (1,110 terrestrial radii); the relative size of sunand earth (5.5:1 in terrestrial radii); and the circumfer-ence of the earth (24,000 mile). On the basis of theseparameters and using simple trigonometric functions,Ibn Mu ā˓dh calculates the atmosphere to be around 52mile high. This figure remained canonical in the LatinWest until the end of the sixteenth century, when TychoBrahe raised the issue of atmospheric refraction toprominence. Within this context, it soon became clearthat Ibn Mu ā˓dh’s calculation was useless because itfailed utterly to take atmospheric refraction intoaccount. Consequently, his figure of 52 mile wasdrastically reduced by Johan Kepler and succeedingastronomers.

See also ▶al-Khwārizmī, ▶Ibn al-Haytham, ▶Astron-omy in the Islamic World

References

Hermelink, H. Tabulae Jahen. Archive for History of ExactSciences 2 (1964): 108–12.

Plooj, Edward B. Euclid’s Conception of Ratio and hisDefinition of Proportional Magnitude. Rotterdam: vanHengel, 1950.

Sabra, A. I. The Authorship of the Liber de crepusculis. Isis58 (1967): 77–85.

Saliba, George. The Height of the Atmosphere According toMu ā˓yyad al-Dīn al ˓Urd. ī, Qut.b al-Dīn Al Shīrazī and IbnMu ā˓dh. From Deferent to Equant. Ed. David A. King andGeorge Saliba. New York: New York Academy ofSciences, 1987. 445–65.

Smith, A. Mark. The Latin Version of Ibn Mu ā˓dh’s Treatise‘On Twilight and the Rising of Clouds’. Arabic Sciencesand Philosophy 2 (1992): 83–132.

Smith, A. Mark and Bernard R. Goldstein. The MedievalHebrew and Italian Versions of Ibn Mu ā˓hd’s ‘On Twilightand the Rising of Clouds’. Nuncius 8 (1993): 611–643.

Villuendas, M. V. La trigonometria europea en el siglo XI:Estudio de la obra de Ibn Mu a˓d, El Kitāb mayhūlāt.Barcelona: Instituto de Historia de la Ciencia de la RealAcademia de Buenas Letras, 1979.

Ibn Mun i˓m

AHMED DJEBBAR

The oldest mathematical work from theMaghreb whichdeals with combinatory problems is the Fiqh al-h. isābof Ibn Mun i˓m, a scholar originally from Andalusia,living in Marrakesh in the Almohad era. To ourknowledge, his book was the first in the entire historyof mathematics to have devoted a whole chapter tothese types of problems and to have stated them andsolved them according to a common procedure.Aside from Ibn ˓Abd al-Malik, the biographers of the

Maghreb do not mention Ibn Mun i˓m, even thoughthey write at length about mathematicians of lessersignificance, and they use the contents of his book. Thelittle information we do have on Ibn Mun i˓m comesfrom his own introduction to his mathematical text,cited above, and from the book of Ibn ˓Abd al-Malik.According to the latter source, Ibn Mun i˓m’s full

name was Ah.mad ibn Ibrāhīm ibn ˓Ali Ibn Mun i˓mal-˓Abdarī. He was originally from the town of Deniaon the east coast of Spain, near Valencia, and he livedin Marrakesh where he taught and where he died in626H/1228. He was known as one of the best scholarsof his era in geometry and number theory. At the age of30, he began to study medicine which he practicedsuccessfully at the same time as his mathematicalactivities.Only three of Ibn Mun i˓m’s numerous mathematical

texts and letters are known today: one on magicsquares, another on geometry, and the third on thescience of calculation. And of these, only the last, Fiqhal-h. isāb, is extant. Ibn Mun i˓m wrote it under the reignof the fourth Almohad caliph, al-Nās.ir (1199–1213).During his reign celebrated scholars like the grammar-ian Abū Mūsā al-Jāzūlī, the algebraist Ibn al-Yāsamīn,and the doctors of the Ibn Zuhr family all lived in theAlmohad capital, or even within the court itself. Thisleads one to believe that there was a variety of scientificactivity, thanks to a generous and often enlightenedpatronage.

1112 Ibn Mun i˓m

Combinatory analysis is taken up the 11th sectionof the first chapter of Fiqh al-h. isāb, entitled “anaccounting of words which are such that human beingscan express them only by one of them.” This section isnot, however, in the eyes of this author, a completeoverview of practical calculations. He takes care toexplain, in the course of his exposition, that heproposes first to treat the problem in a general manner,even though he is obliged, in order to make his ideasclear, to formulate it in specific terms using the Arabicalphabet. In fact, this study goes beyond the linguisticframework in which it is formulated, as much by theway of posing the problems and linking them to eachother, by the methods of reasoning used, as by theestablished results.

Ibn Mun i˓m begins by setting out the problem as amathematician; he defines precisely the framework inwhich he is stating the chosen hypotheses and thedegree of generality researched. Then he establishes,using a set of colors of silk as an abstract model, a rulewhich enables one to determine all the possiblecombinations of n colors p times p. In order to dothat, he constructs, in accordance with an inductivemethod, a triangular numeric table, identifies itselements, with the desired combinations, and deducesthe relationships:

Cpn ¼ Cp�1

n�1 þ Cp�1n�2 þ . . . þ Cp�1

p�1 :

Thus, he presents, to our knowledge for the first time,the famous arithmetical triangle which algebraists fromthe Muslim East like al-Karajī (d. 1029) had alreadyconstructed but for other purposes and using anotherprocedure.

Ibn Mun i˓m’s study continues by establishing, usinginduction, relative formulas with permutation, with orwithout repetitions, of a group of letters such that theygive, by recurrence, the number of possible readings of aword of n letters, taking into account all the signs (vowelsand sukūns for Arabic) used by a given language. This isthe content of problems 2, 3, and 4. In problem 5, theauthor concludes the first part byestablishinga formulaofarrangements, without repetition, of n objects p times p,which take into account the vowels and the sukūnaccompanying the letters.

The second part, much longer, seeks to enumeratethe combinations with repetitions, adopting a methodanalogous to the preceding one and which necessitatesrecourse to the table of numbers. It was moreover thissame method that the French scholar Mersennerediscovered and applied to his work in the seventeenthcentury.

To set up problem 6, Ibn Mun i˓m goes back tohis model of bunches and proposes to solve adifficult dilemma, apparently removed from the initialproblem and stated thus: being given threads of silk

in n colors, we want to determine the number ofbunches it is possible to make with p threads of kcolors, so that p1, p2,… , pk threads are, respectively, ofthe same color.

All these propositions, and even more the techni-ques, allow the resolution of the problem which IbnMun i˓m formulates as follows: to determine thenumber of words of 1–10 letters which it is possibleto make with the letters of the Arabic alphabet,including all possible repetitions of letters in a words,and including vowels and the sukūn which can appearon letters.

The third part of his study includes, along withseveral applications, a series of tables which enablesthe determination, more and more closely, of all theelements (Pn, An, Cn,…) which occur in the counting ofwords that it is possible to pronounce in a givenlanguage.

In addition to the results included in this chapterof Fiqh al-h. isāb, the way in which Ibn Mun i˓m estab-lished his results is also notable. In fact, he uses twotypes of reasoning which can be called inductive andcombinatorial.While inductive reasoning is a traditionaltool of Islamic mathematics with its privileged domainsand unique stature, one cannot say the same for com-binatorial reasoning which appeared, to our knowledgefor the first time, in theFiqh al-h. isāb. His systematic useof combinatorial reasoning for establishing generalpropositions appeared as a clear acknowledgment ofits mathematical character.

One can even suppose that if combinatorial reasoninghad enjoyed a quantitative development in the fieldof application, it would have resulted in its explicitrecognition as a process of reasoning beside analysis,synthesis, induction, and reasoning ad absurdum.

The elaborate nature of his procedures and resultswhich appear in the Fiqh al-h. isāb, as well as thespirit of the method which emerged from them leadsto the theory that the beginning of the mathematiza-tion of combinatorial problems within the frameworkof Arabic science occurred prior to the work of IbnMun i˓m.

While we await the confirmation, or correction, ofthis conjecture, the Fiqh al-h. isāb remains the oldestknown Arabic work from the Muslim West in which anautonomous chapter on combinatorial analysis ap-peared. But its importance does not end there: withregard to the linguistic tradition of the Maghreb, thebook was a culmination in that it laid out a generalsolution to a given problem. Also, for mathematics, thework represents an important link, marking the end ofone stage in the progress of combinatorics, that ofcalculation using tables, and the beginning of anotherstage, that of the extension of formulas and their use insolving problems.

Ibn Qunfudh 1113

See also: ▶Combinatorics in Islamic Mathematics

References

Djebbar, A. Enseignement et recherche mathématiques dansle Maghreb des XIIe –XIV e siècles. Paris: PublicationsMathématiques d’Orsay, 1981.

Djebbar, A. L’analyse combinatoire au Maghreb: l’exempled’Ibn Mun i˓m (XIIe–XIIIe siècles). Orsay, France: Uni-versité de Paris-Sud, 1985.

Rashed, R. The Development of Arabic Mathematics:Between Arithmetic and Algebra. Dordrecht and Boston:Kluwer Academic, 1994.

Ibn Qunfudh

I

Y. GUERGOUR

Abū’1˒AbbāsAh.med Ibn al-H. asan Ibn ‘Ali Ibn al-Khat.ībwas known under the two names of Ibn Qunfudh andIbn al-Khat.īb. He was born in 710 AH (AD 1339) inConstantine, Algeria and came from an old family whichwas cultured and well to do. We know that Ibn Qunfudhbegan his studies with his father and his maternalgrandfather, in order to follow them eventually underthe direction of other professors from his same town.

After his elementary education, he returned to Fez,in Morocco, where he remained for 18 years. There hestudied with several professors, covering differentscientific themes, and teaching and publishing someof his own work. We know that it is in this city that heedited in 771 (1370) his most important mathematicalwork, the H. at.t. an-niqāb a˒n wujūh a˒māl al-h. isāb,which is a commentary on the Talkhīs. a˒māl al-h. isāb ofIbn al-Bannā ,˒ written in 721 (1321). We think that heacquired his advanced education either completely orpartially during his stay in Fez.

During the period of famine which raged in all ofMaghreb in 776 (1374), Ibn Qunfudh went back toConstantine in order to take up duties as a khat.ib(preacher), mufti (jurist), and qād. ī (judge). At the sametime, he devoted himself to the teaching and editing ofscholarly work. No information has come down to uson the subject of the contents of this teaching, and wedo not even know if he taught the contents of his ownmathematical writings at Constantine or in the citieswhere he was posted, or even if he was content only toedit them, following in that the tradtion of several olderauthors, who wrote on subjects which were verydifferent from each other without having taught them.

What follows is an attempt to give a glimpse of IbnQunfudh’s contributions to mathematics, of which weknow only four titles:

1. Mabād’ as-sālkin f ī sharh rajz Ibn al-Yāsamīn(Principles for Those who are Concerned with theCommentary on the Poem of Ibn al-Yāsamīn). IbnQunfudh began this poem according to the traditionalprocedure of commentators of the Middle Ages.What is not traditional is his use of mathematicalsymbolism to resolve equations and to representpolynomials. This was to become normal practiceduring this period, since this commentary wasadopted by his students. The symbolism was univer-sally used inmathematical works fromMaghreb. Thishypothesis is reinforced by the presence of this samesymbolism in the bookH. at.t. an-niqāb and in the bookwritten by Ya q˒ūb al-Muwāh. idī Tahs.īl al-munā f īsharh Talkhīs. Ibn al-Bannā.

2. Bughyat al-fārid. min al-h. isāb wa l-farā’id (TheDesire of the Genealogical Specialist to KnowArithmetic and Successional Division). To this day,no copy of this book has been found.

3. at-Talkhīs. f ī shzarh at-Talkhīs. (Abridged Commen-tary on Talkhīs.). This is a resume of H. at.t. an-niqāb,of which two copies are extant today.

4. H. at.t. an-niqāb a˒n wujūh a˒māl al-h. isāb (Lifting theVeil on the Operations of Calculation). Five copiesof this work are extant.

Since this is Ibn Qunfudh’s most important work, it isuseful to describe certain aspects of its contents. Readingit permits us to make several important observations onmathematical writing in this era. The author begins hisbook with some advice and directions designed to facil-itate the reading of any book; then he provides a detailedlist of the writings of Ibn al-Bannā .˒ In the beginning ofeach chapter, he gives an abstract of its contents,something which one finds nowhere else in the literatureof other mathematicians of this time. It is also importantto note again the existence of Ibn Qunfudh’s mathemat-ical symbolism, particularly in the chapters on rootsand on algebraic equations. However, recent researchreveals that this symbolism had been used previously atthe end of the twelfth or beginning of the thirteenthcentury, especially in IbnYāsamīn’s bookTalqīh. al-afkār.Elsewhere, Ibn Qunfudh supplies arithmetic rules whichone does not find in Ibn al-Bannā ’˒s work, notably in thechapter on the product. Ibn Qunfudh’s terminology alsodiffers significantly from Ibn al-Bannā ’˒s.Finally, one finds in the work of Ibn Qunfudh

an equation of which the second number is zero, anequation which had formerly been studied by Ibn Badr.His originality lies in the symbolic way in which heexpressed it:

or, in modern symbols, 8.r–7 = 0.Ibn Qunfudh died in 810 AH (AD 1407).

1114 Ibn Qutayba

See also: ▶Ibn al-Bannā

References

Djebbar, A. Enseignement et recherche mathématiques dansle Maghreb des XIIIe—XIVe siècles. Paris: PublicationsMathématiques d’Orsay, Number 81–02, 1981.

---. L’analyse combinatoire au Maghreb: l’exemple d’IbnMun .˒ Paris: Publications Mathématiques d’Orsay, Number85–01, 1985.

---. Quelques apects de l’algèbre dans la tradition mathéma-tique arabe de l’occident musulman. Colloque Maghrébinsur l’histoire des mathématiques Arabes, 1–3 décembre1986. Alger: la Maison des livres, 1988.

Guergour, Y. Dirāsa a˒n Ibn Qunfudh was tah. qīq sharhihi liurjuzat Ibn Yāsamīn al-jabria. Mémoire de D. E. A. enHistoire des Mathématiques E.N.S. d’Alger, 1986.

---. Les écrits Mathématiques d’Ibn Qunfudh al-Qasant.īnī(810/1406). Doctoral thesis, Algeria, 1990.

Ibn Qunfudh. Uns al-faqīr wa i˒zz al-h. aqīr. Ed. Muhamed al-Fasi and Adolphe Faure. Rabat: Université de RecherchesScientifiques, 1965.

Zemouli, T. Les écrits mathématiques d’Ibn al-Yāsamīn.Doctoral thesis, Algeria, 1992.

Ibn Qutayba

PAUL KUNITZSCH

Ibn Qutayba, Abū Muh.ammad ˓Abdallāh ibn Muslim,was born in 828 in Kufa or Baghdad, and died in 884 or889 in Baghdad.

Ibn Qutayba was a scholar of typical Arabic–Islamiceducation. His studies included all branches of thetraditional Arabic and Islamic knowledge of his time:religion, history, biography, philology, lexicography,literature, and some science. He left twenty works ofvarying lengths covering all the fields mentioned. In hiscareer, for some years he was qād. ī (a judge accordingto Islamic rules) in Dinawar (northern Iran); later helived and taught in Baghdad, where he also died. Ofparticular scientific interest is his Kitāb al-anwā˒ (Bookon the anwā )˒. Anwā˒ are asterisms and stars used bythe Arabs in pre-Islamic and early Islamic times todetermine seasons, predict weather—especially rain,and guide them in their nightly desert travels. ManyArabic philologists and lexicographers wrote books ofthis type, but most of these did not survive. ThereforeIbn Qutayba’s Book on the anwā ,˒ which was printed inArabic, in Hyderabad/Deccan (India) in 1956, is ofgreat interest. In it, the author has assembled informa-tion on the popular astronomical and meteorologicalknowledge of the old Arabs, from the time before theiracquaintance with Greek, Persian, and Indian astronomy.

Facts, traditions, terminology, and nomenclature areamply described. Much of this material continued to beused later in the most active period of Arabic – Islamicastronomy.And some of it even lived on into our time, as,for example, the star name Aldebaran (for α Tauri).

References

Brockelmann, Carl. Geschichte der arabischen Litteratur.Leiden: Brill, I, 1943. 120–3; Supplement I, 1937. 184–7.

Huseini, I. M. The Life and Works of Ibn Qutayba. Beirut:American Press, 1950.

Lecomte, Guy. Ibn Qutayba, l'homme, son oeuvre, ses idées.Damascus: Institut français de Damas, 1965.

Ibn Rid.wan

ALBERT Z. ISKANDAR

Abu’l-H. asan ˓Alī Ibn Rid.wān ˓Alī Ibn Ja f˓ar, a self-educated physician philosopher, was born in AD 998 atGīzah, a suburb south of Cairo (al-Fust.āt.). He was theson of a poor baker ( farrān) and had to earn money inhis youth by practicing medicine, teaching, and tellingpeople’s fortunes from astrological signs. When he was59, he wrote a book entitled Fī Sīratihī (On His OwnConduct). The work is now lost, but its text is partlypreserved in Ibn Abī Us.aybi a˓’s ˓Uyūn al-Anbā˒ fīT. abaqāt al-At.ibbā˒ (Sources of Information About theClasses of Physicians).

In his youth, he believed in astrology ( i˓lm al-nujūm)and was convinced that the stars at the time of hisbirth indicated a prosperous medical career. To realizehis ambition, he first sought out a popular teacherin Cairo, who instructed Ibn Rid.wān to memorizeH. unayn Ibn Ish.āq’s (d. AD 873) Kitāb al-Masā i˒lfi’l-T. ibb li’l-Muta a˓llimīn (Questions on Medicine forStudents). Ibn Rid.wān watched him teaching: pupilsread the text; the teacher listened but did not utterone word of explanation and did not even bother tocorrect their errors. Ibn Rid.wān sought to find otherteachers and put questions to each of them, based onthe writings of Hippocrates and Galen, which theydisplayed on shelves in their private libraries. Heconcluded that they merely knew the titles of books butwere ignorant of their contents. He pondered overtraveling to Iraq for further education, but financialdifficulties prevented his going there. He decided onself-education at the tender age of 15. From perusingGalen’s On the Doctrines of Hippocrates and Plato, heconcluded that he should first study geometry and

Ibn Rushd (Averroës) 1115

I

logic. He studied the well-known books on these twosubjects, then proceeded to read textbooks on medicineproper. In this way he reached an understanding of theprinciples of the art of healing.

Ibn Rid.wān worked very hard as a practicing doctoruntil he reached the age of 32, when he became wellknown and earned enough money to build his ownresidential Palace of Candles (Qas.r al-Sham )˓. At theage of 59 he divided his time between practicingmedicine, daily physical exercise (al-riyād.ah), andreading books on literature, Islamic law, and medicine.His fame reached the Fātimid Caliph al-Mustans.ir(r. AD 1036–1094), who appointed him Chief ofPhysicians (Ra ī˒s al-At.ibbā˒) in Egypt. He was kind-hearted, treated the poor for free, and was alwayswilling to extend a helping hand to the needy.

In old age, Ibn Rid.wān’s mind became disturbed(taghayyar a˓qluhu) as a result of being robbed ofall his cherished possessions. He had adopted anorphan young girl whom he brought up in his ownhouse. She absconded with all the precious items hehad accumulated and 20,000 gold dīnārs which he hadkept in the house. An extensive search for the girl wasabortive. Ibn Rid.wān died in AD 1067.

Among Ibn Rid.wān’s extensive bibliography are histreatise Fī Daf ˓Mad.ārr al-Abdān fī Ard. Mis.r (On thePrevention of Bodily Ills in Egypt) and the Al-Nāfī ˓ f īKayfiyyat Ta l˓īm s.inā˓ at al-T. ibb (Useful Book on theQuality of Medical Education).

In On the Prevention of Bodily Ills, he describes theNile and the Muqat.t.am Hills on both sides of the river.The hills in the east hold back the “hot and humid”winds, which are most favorable for the temperament(mizāj) of animals and which do not reach al-Fust.āt..Ibn Rid.wān gives an account of “the six non-naturalcauses” (al-asbāb al-sitta al-d.arūriyya) which deter-mine health and sickness: the air surrounding thebody, food and drink, movement and rest, sleep andwakefulness, retention and evacuation, and psychicevents.

Ibn Rid.wān was discourteous in criticizing membersof the medical profession. For example, chapter 5 ofthis treatise is entitled “On the Incorrectness of Most ofIbn al-Jazzār’s [d. AD 1009] Reasons for the UnhealthyAir in Egypt.” Furthermore, disagreements arose withIbn But.lān of Baghdad. These are well documented byMeyerhof and Schacht (1937).

In his Useful Book, Ibn Rid.wān preserved forposterity a unique document, the late Alexandrianmedical curriculum (sixth to seventh century AD). Init he attributes the decline of medicine in his timeto the popularity of poor-quality compendia (kanānīsh)and summaries and commentaries of the books ofHippocrates and Galen, compiled by incompetent

physicians. The Alexandrian curriculum specifies thetitles of textbooks of logic, medicine proper, and mathe-matics (including astronomy). It consists of preparatory(introductory) courses and main courses. The prepara-tory courses contain optional subjects, includinglanguage and grammar, and compulsory subjects: phys-ics, arithmetic, numerals, measurement, geometry, thecompounding of drugs, astrology, and ethics.The main courses include logic and medicine proper.

Sixteen of Galen’s books were to be studied in sevengrades: Grade 1 included Galen’s On Sects, On the Artof Physics, On the Pulse, To Teuthras, and To Glauconon Therapy. In the final and seventh grade, studentsstudied Galen’s On the Method of the Preservation ofHealth.

See also: ▶Ibn But.lān

References

Aouad, Maroun. La Doctrine rhétorique d’Ibn Rid.wān etla ‘Didascalia in Rhetoricam Aristotelis Ex Glosa Alphar-abii’.Arabic Sciences andPhilosophy 7.2 (1997): 163–245.

---. La Doctrine rhétorique d’Ibn Rid.wān et la ‘Didascalia inRhetoricam Aristotelis Ex Glosa Alpharabii’. ArabicSciences and Philosophy 8.1 (1998): 131–60.

Dols, Michael W. Medieval Islamic Medicine. Ibn Rid.wān’sTreatise On the Prevention of Bodily Ills in Egypt.Berkeley: University of California Press, 1984.

Ibn Abī Us.aybi a˓. ˓Uyūn al-Anbā˒ fī T. abaqāt al-At.ibbā .˒ Ed.August Müller. Vol. 2. Königsberg: Selbstverlag, 1884.99–105.

Iskandar, Albert Z. An Attempted Reconstruction of the LateAlexandrian Medical Curriculum. Medical History 20.3(1976): 235–58.

Meyerhof, Max and J. Schacht. The Medico-PhilosophicalControversy Between Ibn But.lān of Baghdad and IbnRid.wān of Cairo. A Contribution to the History of GreekLearning Among the Arabs. Faculty of Arts, PublicationNo. 13. Cairo: The Egyptian University, 1937.

Seymore, Jennifer Ann. The Life of Ibn Ridwan and HisCommentary on Ptolemy’s Tetrabiblos. Ph.D. Dissertation,Columbia University, New York, 2001.

Ibn Rushd (Averroes)

ALBERT Z. ISKANDAR

Abu’l-Walīd Muh.ammad ibn Ah.mad ibn Muh.ammadibn Rushd (Averroës, AD 1126–1198), a native ofCordoba, Spain, was the namesake of his famousgrandfather. Later, to avoid any confusion, he wasnicknamed al-h. af īd (grandson). Like his father and

1116 Ibn Rushd (Averroës)

grandfather, he was a well-known jurist. By profes-sion, following in the footsteps of his father, hebecame a qād. ī (judge), who specialized in religiousmatters, and at one time was the Imam of the greatmosque of Cordoba. He adhered to the Mālikī sect,one of the four great sects of Islam, and wrote Kitābal-Muqaddimāt al-Mumahhidāt (A Book of Intro-ductions that Pave the Way), for the followers ofthe sect.

At his father’s insistence, Ibn Rushd studied Islamiclaw (Sharī a˓) under the teacher, al-H. āfiz. AbūMuh.ammad Ibn Rizq. Ibn Rushd also studied thescience of Tradition (H. adīth), but he is known to havebeen more interested in Islamic law. He memorized theMuwat.t.a˒ of Imam Mālik and was also greatly im-pressed by the Ash a˓rite science of Kalām (Theology).Later, he turned against the Ash a˓rī school of thoughtand attacked its proponent, the Imam al-Ghazālī (d. AD1111). Ibn Rushdwas also acquainted with the doctrinesof the Mu t˓azila theology.

His teachers of medicine were Abū Marwān IbnJurrayūl, a first-class practitioner, and Abū Ja f˓arHārūn al-Tarjālī, a well-known physician philosopherin Seville, who was knowledgeable about Aristotelianphilosophy, as well as the medical writings ofthe Ancients. Al-Tarjālī was employed by the Almohad(al-Muwah. h. id) ruler Abū Ya q˓ūb Yūsuf (r. AD 1163–1184). Abū Yūsuf Ya q˓ūb al-Mans.ūr (r. AD 1184–1199), before succeeding his father, attended meet-ings in Seville, to which notable philosophers,physicians, and poets were invited. Abū Bakr IbnT. ufayl (Abubacer), Ibn Zuhr (Avenzoar), and IbnRushd were regular attendants at these meetings.Ibn Rushd’s education under al-Tarjālī qualified himas a physician-philosopher; his studies in religiouslaw, under al-H. āfiz. , entitled him to be considered ajurist ( faqīh).

In 1153, when he was in Marrakech (Morocco), IbnRushd supported the Almohad ruler ˓Abd al-Mu˒min(d. AD 1163) in furthering education by foundingcolleges. From his commentary on Aristotle’s DeCaelo, one learns that Ibn Rushd conducted astronom-ical observations when in Marrakech, and in hiscommentary on the Metaphysics, he mentions hisyearning for his early studies in astronomy. Ibn Rushdstudied the writings of Arabic-speaking astronomersand expressed his own opinion regarding the threekinds of planetary motions: those that can be detectedby the naked eye, those that can be seen by instru-ments of observation (remarking that some occurredover long periods of time that exceeded the lifetimeof observers), and those planetary movements whoseexistence can only be surmised by reasoning. BetweenAD 1169 and 1179, Ibn Rushd visited many places inthe Almohad realm. He was actively researchingmatters pertaining to astronomy when he met Ibn

T. ufayl, a philosopher and astronomer in his own right.Ibn T. ufayl enhanced Ibn Rushd’s career by intro-ducing him to Abū Ya q˓ūb Yūsuf, who appointed IbnRushd as qād. ī of Seville in AD 1169. Ibn Rushdreturned to Cordoba in AD 1171, at which time he wasstill holding the office of qād. ī. In AD 1182, hesucceeded Ibn T. ufayl as a personal doctor to AbūYa q˓ūb Yūsuf, and was elevated to the office of grandqād. ī of Cordoba.

For 10 years Ibn Rushd enjoyed the patronage ofAbū Ya q˓ūb Yūsuf. Out of jealousy, jurists (al-fuqahā˒)of the Mālikī sect, whose influence had grown as aresult of their religious zeal during the period of theCrusades, successfully conspired against him for hisfree-minded views. He was summoned to appear incourt, and his philosophical writings were deemedcontrary to the teachings of Islam. Ibn Rushd fell fromgrace in AD 1195 and was banished to Lucena, aprovince of Cordoba.

Very little is known about Ibn Rushd as a teacher ofmedicine. Nevertheless, the names of two of hisstudents are known: ˓Abd Allāh al-Nadrūlī and Ī˓sāibn Ah.mad ibn Muh.ammad ibn Qādir. The lattertranscribed the whole text of Ibn Rushd’s book Al-Kulliyyāt (Generalities) from the author’s own auto-graph, during his lifetime, and with his approval.

Kitāb al-Kulliyyāt (Latin, Colliget) consists of sevenbooks: Tashrīh. al-A d˓.ā˒ (The Anatomy of Organs),al-S. ih. h. a (Health), al-Marad. (Disease), al- A˓lāmāt(Symptoms), al-Adwiya wa’l-Aghdhiya (Drugs andFoods), Hif z.-al-s. ih. h. a (Hygiene), and Shifā˒ al-Amrād.(Recovery from Disease). The purpose of the book,according to the author, is to provide medical men withan introduction to concise accounts of the differentparts of medicine (ajzā˒ al-t.ibb).

Scientific collaboration existed between the eminentpractitioner Ibn Zuhr (Avenzoar, d. AD 1162) and IbnRushd. Ibn Rushd asked Ibn Zuhr to write a book ontherapy, which he did. It was called al-Taysīrfī’l-mudāwāt wa’l-tadbīr (An Aid to Therapy andRegimen). Al-Taysīr and the Kulliyyāt together weremeant to cover the whole science of medicine, possiblyinstead of Ibn Sīnā’s (Avicenna, d. AD 1037) Kitābal-Qānūn fi’l-T. ibb (Canon of Medicine), which IbnZuhr severely criticized.

A merchant from Baghdad presented Ibn Zuhrwith a beautifully transcribed and ornamented copyof Ibn Sīnā’s Kitāb al-Qānūn. After reading it for thefirst time, Ibn Zuhr condemned the book and kepttearing off the margins of its leaves, which he usedfor jotting down prescriptions for his patients. It tookalmost a century before a copy of Kitāb al-Qānūn,completed by its author in Hamadan (Persia), actuallyreached Cordoba, Ibn Rushd’s home town.

See also: ▶Ibn T. ufayl, ▶Ibn Sīnā

Ibn Sahl 1117

References

Arnaldez, Roger and Albert Zaki Iskandar. Ibn Rushd.Dictionary of Scientific Biography. Vol. 12. New York:Scribner’s Sons, 1970–1980. 1–9.

Fakhry, Majid. Averroës (Ibn Rushd): His Life, Works andInfluence. Oxford: Oneworld, 2001.

Ibn Abī Us.aybi a˓. ˓Uyūn al-Anbā˒ f ī T. abaqāt al-At.ibbā .˒Vol. 2. Ed. August Müller. Königsberg: Selbstverlag, 1884.75–8.

Ibn Rushd. Kitāb al-Kulliyyāt. MS No. 14524.b.61. London:The British Library, 1987.

Ibn Sahl

Ibn Sahl. Fig. 1 Refraction in lenses.

I

ROSHDI RASHED

Ibn Sahl, Abū Sa d˓ al-˓Alā ,˒ was a first-class mathema-tician. From his correspondence as well as from diverseinformation transmitted by mathematicians of thesecond half of the tenth century, we can deduce thathe flourished under the Buwayhid Dynasty, andprobably in Baghdād, between 970 and 990. Many ofIbn Sahl’s important writings have been lost, namelytwo treatises, On the Measurement of the Parabola andOn the Centers of Gravity, and a kind of anthology ofproblems about which we have no direct information.His book Fī al-H. arrāqāt (On Burning Instruments)was also on the point of being lost. This book, writtenin Baghdād around 984, is the first known contributionon the geometric theory of lenses.

Let us begin with the contribution of Ibn Sahl tooptics. He wrote a memoir on the transparency ofthe celestial sphere, which was commented on by Ibnal-Haytham. The memoir and the commentary havecome down to us. In this, composed in the course of hisreading of Book Vof Ptolemy’s Optics, Ibn Sahl takesup not only the rules of refraction set out by hispredecessor, but also demonstrates that every medium,including the celestial sphere, is invested with a certainopacity which defines it. Ibn al-Haytham had alreadycaptured this idea perfectly when, on reading this samememoir of Ibn Sahl, hewrote that his predecessor wantedto demonstrate that “there is no limit to transparency,and, for each transparent body, another always existswhich is more so.” That is to say that the mathematicianbetter understands the notion of a medium and itsdefinition by a certain characteristic opacity.

But Ibn Sahl’s real discovery takes place when heposes the still unthought-of question of burning byrefraction. He no longer defines the medium by acertain opacity, but characterizes it by a constant ratio.It is this concept of constant ratio distinguishing themedium which is the masterpiece of his study of

refraction in lenses. This ratio, postulated by Ibn Sahlbut never calculated, is nothing but the inverse ofthe refraction index n of the medium in relation to air.It therefore deals with Snellius’ law of refraction,its formulation being very close to Snellius’ ownformulation some six centuries later. Let us look againat On Burning Instruments (Fig. 1).At the beginning of the study of refraction in lenses,

Ibn Sahl considers a plane surface GF limiting a pieceof crystal. He considers the straight line DC followingwhich light propagates in the crystal, the straight lineCE according to which it refracts in the air, and theperpendicular at G to the surface GF which cuts thestraight line CD at H and the refracted ray at E.Here Ibn Sahl clearly applies the law by which the

ray CD in the crystal, the ray CE in the air, and theperpendicular GE to the surface plane of the crystal, areall on the same plane. As usual, with no conceptualcomment, he writes:

The straight line CE is therefore smaller than CH.We separate from the straight line CH the straightline CI equal to the straight line CE; we divide HIin half at point J; we set the ratio of the straightline AK to the straight line AB equal to the ratio ofthe straight line CI to the straight line CJ; weextend the straight line BL along AB and set itequal to the straight line BK.

In these sentences, Ibn Sahl concludes that CE/CHis less than 1, which he will use throughout his research

1118 Ibn Sarabi (Serapion)

on lenses constructed in the same crystal. He will notfail to give this same ratio again, nor to reproducethis same figure, each time he discusses refraction inthe crystal.

This ratio is nothing but the inverse of the index ofrefraction in the crystal in relation to air. In fact, let usconsider i1 and i2, the angles formed, respectively, byCD and CE with the perpendicular GH. One has

1n¼ sin i1

sin i2¼ CG

CHCECG

¼ CECH

:

Ibn Sahl takes on segment CH point I such thatCI = CE, and point J at the middle of IH. One has

CICH

¼ 1n:

The division CIJH henceforth characterizes the crystalfor all refraction.

Ibn Sahl made innovations not only in optics, butalso in mathematics. Among his mathematical inven-tions, I shall mention only one paper, set down as afollow-up to his contemporary, the mathematician al-Qūhī: his study of the method of projection of thesphere. Al-Qūhī is, in fact, the author of a treatise onThe Art of the Astrolabe by Demonstration. Thistreatise is composed of two books, of which the firstopens with an introductory chapter on the theory ofprojections. The propositions which al-Qūhī set forthseemed “difficult to understand” to one of his contem-poraries, who turned to Ibn Sahl for clarification of thenotions found therein and for the proof by synthesis ofwhat al-Qūhī showed by analysis. We have here asituation of privileged history: we are witness to theelaboration of a new chapter of geometry by twocontemporary mathematicians.

In conclusion, I remark upon the emergence of IbnSahl, a figure until recently almost unknown, and twochapters: anaclastics and the study of projection of thesphere. Ibn Sahl also made a substantial contribution ininfinitesimal mathematics as well as in constructionproblems – the regular heptagon, for instance.

References

Bellosta, Hélène. Burning Instruments: From Diocles toIbn Sahl. Arabic Sciences and Philosophy 12 (2002):285–303.

Kahl, Oliver. A Note on Sabur ibn Sahl. Journal of SemiticStudies 44.2 (Autumn 1999): 245–9.

Rashed, R. A Pioneer in Anaclastics: Ibn Sahl on BurningMirrors and Lenses. Isis 81 (1990): 464–91. Rpt. inOptique et mathématiques: recherches sur l’histoire de lapensée scientifique en arabe. Aldershot: Variorum, 1992.

---. Géométrie et dioptrique au X e siècle: Ibn Sahl, al-Qūhī etIbn al-Haytham. Paris: Les Belles Lettres, 1993.

Rashed, R. (ed. and co-author). Encyclopedia of the Historyof Arabic Science. 3 vols. London: Routledge, 1996.

Ibn Sarabi (Serapion)

E. RUTH HARVEY

There are two different Arab authors known to themedieval Latin west as “Serapion,” and the confusionbetween them in all of the authorities seems inextricable.The elder of the two authors was a Syrian, Yuh.ānnā ibnSarabiyun, who lived in the ninth century. He wrote twobooks in Syriac, which were translated into Arabic: theyare called the Large Kunnāsh (it was in twelve parts) andthe Small Kunnāsh (in seven parts). Manuscript copiesof the Arabic versions exist in European libraries; whatsounds like a whole copy of the Large Kunnāsh is inIstanbul. Both works deal with medicine and diet, but notsurgery; al-Rāzī (Razes), who may have been a youngercontemporary, cites Serapion, naming the Kunnāsh, and˓Alī ibn A˓bbās al-Majūsī (d. 994) criticizes Serapionfor ignoring surgery. The Small Kunnāsh was translatedinto Latin by Gerard of Cremona (d. 1187) and entitledPractica Joannis Serapionis dicta Breviarium. Thereare many manuscript copies of this version and someearly printed texts. Moses ben Mazliach translatedGerard’s version into Hebrew, and a manuscript of thistranslation still survives.

The younger Serapion is an even more obscurefigure. He was the author of a treatise on drugs calledKitāb al-adwiya al-mufrada, which was translated intoLatin as Liber de medicamentis simplicibus by Simonde Cordo of Genoa and Abraham of Tortosa in about1290. The younger Serapion cannot have lived earlierthan the eleventh century, because he cites among hisauthorities not only al-Rāzī, but also Ibn al-Wāfid(997–1075). There are many manuscript copies of theLatin translation, and several early prints. Usually theworks of both Serapions appear together. In the Latintext, the author explains that he intends to collect andreconcile the views of Dioscorides and Galen on a widevariety of medicinal substances, and then to add inthe opinions of others. In his chapter on pearls, forinstance, he describes the generally accepted power ofpearls to strengthen the heart; he then goes on to citefour Arab authorities on the effects of pearls on theeyesight, the blood, the nerves, melancholia, and as adentifrice.

See also: ▶al-Rāzī, ▶al-Majūsī

References

Campbell, Donald. Arabian Medicine and Its Influence on theMiddle Ages. 2 vols. London: Kegan Paul, Trench, Turbner& Co., 1926.

Ibn Sīnā (Avicenna) 1119

Peters, Curt. Johannan b. Serapion. Le Muséon 55 (1942):139–42.

Sezgin, Fuat. Geschichte des Arabischen Schrifttums III:Medizin, Pharmacie, Zoologie, Tierheilkunde, bis ca. 430 H.Leiden: Brill, 1970. 228, 240.

Ibn Sına (Avicenna)

I

MEHDI AMINRAZAVI

Abū ˓Alī al-H. usain ibn ˓Abdallāh ibn Sīnā (980–1037),also known as Avicenna, was born in the city ofBūkhārā in the Eastern part of Persia into an Isma i˒lifamily. He demonstrated an incredible genius forlearning, and having mastered the Qu r˒ān and thesciences of his time, became a physician at age 16. IbnSīnā gained favor with the Sāmānid dynasty for havingcured Prince Nūh. ibn Mans.ūr and was thus allowed touse the royal library. He mastered other sciences suchas psychology, astronomy, chemistry, and pharmacolo-gy by age 18, and toward the end of his life said he hadlearned everything he knew by then.

Ibn Sīnā lived in a tumultuous time when differentprinces were engaged in a power struggle, resulting inhis traveling from city to city. He first went to Gorgān,an area close to the Caspian Sea, crossing the desert onfoot, and after a while traveled to Khorāsān, Rayy, andQazwīn, until he finally settled in Hamadān at therequest of prince Shams al-Dawlah. In 1022, followingthe death of the prince, Ibn Sīnā went to Is.fahān wherehe found the peace and serenity that the intellectual lifedemands. In 1037 while traveling with ˓Alā˒ al-Dawlahhe became ill and died as the result of colic. He isburied in Hamedan.

Ibn Sīnā gained the title of Shaykh al-Ra ī˒s (Masterof the Wise) because he composed numerous treatises,276 of which have been alluded to by his commentators.It is noteworthy that he wrote a great number of theseworks on horseback while fleeing from one city toanother.

Ibn Sīnā’s most extensive and elaborate work is Kitābal-shifā˒ (The Book of Healing) which itself consists offour segments: al-Mant.iq (Logic), Tabī i˓yyāt (NaturalPhilosophy), Riyād.āyāt (Mathematics), and Ilāhāyyāt(Metaphysics). To this monumental work should beadded Kitāb al-nijāt (The Book of Deliverance), asynopsis of the Shifā ,˒ and his last major work al-Ishārātwa’l-tanbīhāt (The Book of Directives and Treat-ments). Among his other philosophical works areU˓yūn al-h. ikmah (Fountain of Wisdom), Kitāb al-hi-dāyah (The Book of Guidance), al-Mabda˒wa’l-ma ā˓d(The Book of Origin and End), and the first major workwritten in Persian for A˓lā˒ al-Dawlah, Dānishnāmah-yiA˓lā ī˒ (The Book of Knowledge). Finally, there are a few

workswhich aremystical and visionary, such asH. ayy ibnYaqz.ān (Son of the Living Awake), and Risālat al-t.aīr(Treatise of the Bird).Ibn Sīnā was a great synthesizer in that he not only

incorporated the ideas of some of his predecessors suchas al-Kindī and al-Fārābī, but also made extensive useof Greek philosophy, in particular Neoplatonism, Platoand Aristotle. From Plotinus he adopted the emanationscheme, from Plato his theory of archetypes, and fromAristotle his logic, physics, and psychology. Thegenius of Ibn Sīnā was in interpreting these differentthoughts within the unitary matrix of Islam.Ibn Sīnā has been called “philosopher of being” for

he brought the question of being and the study ofontology to the forefront of philosophical debates andthereby corrected a deficiency that he saw in Greekphilosophy, in particular in Aristotle. Ibn Sīnā dividedall beings into three categories: necessary, contingent,and impossible. Furthermore, he argued that existentbeings were made up of an essence and existence. Thisdistinction became the central theme of medievalontological discussions as well as of the subsequentdebates within the Islamic philosophical tradition.Ibn Sīnā, who had studied the Ptolemaic and

Aristotelian systems, adopted the Islamic astronomicalview based on the nine spheres and interpreted themwithin the scheme of the emanation of intellects. Eachorder of intellect accordingly corresponds to one of theheavens. For example, the second intellect correspondsto the highest heaven which is located above the fixedstars, and the tenth intellect corresponds to the moonbelowwhich the corporeal domain of ourworld is located.

MedicineIbn Sīnā was in the tradition of such grand Muslimphysicians as al-Rāzī and al-Majūsī. By the age of 20,he had already become an accomplished physician andgained the respect of the court for having cured severalmembers of the royal family. Eventually he came to beknown as the “prince of physicians”. He is the author ofthe Qānūn al-T. ibb (The Canon of Medicine), whichbecame a standard text both in the Christian West andthe Islamic world. In addition to his magnum opus, IbnSīnā wrote a number of treatises on medicine both inArabic and Persian some of which deal with particulardiseases. He also wrote a book in which principles ofmedicine are written as poetry in order to facilitate theirmemorization by medical students.In medicine, Ibn Sīnā was in many ways a follower

of Greek ideas on medicine. However, he made thefollowing revisions:

1. Unified the central principles of Greek medicine andinterpreted them within an Islamic framework.

2. Made the theoretical and practical aspects ofmedicine represent a unified whole.

1120 Ibn Sīnā (Avicenna)

3. Documented the effects of medications on the bodyand commented on the necessity of a methodologyin the study of pharmacological issues.

4. Introduced a number of medications and treatmentsfor illnesses unknown to Greeks.

Ibn Sīnā believed that the science of medicine wasdivided into two categories, theoretical and practical.Illnesses were brought about either by internal or externalcauses. Internal illnesses were caused by an imbalanceof temperament in the human body. These causes couldalso be the result of psychological elements.

Ibn Sīnā is known to have prescribed a variety oftreatments for ailments, ranging from psychotherapyand diet to exercising. In the first volume of the Canonof Medicine, he states that medicine is the science ofknowing the structure of the human body, and he goeson to discuss the fundamental principles necessary tomaintain human health. He discusses surgery as anindependent branch of medicine and elaborates on thescience of anatomy. In the second volume, Ibn Sīnāexplains various healing properties of simple andcompound drugs and their various applications. In thethird and fourth volumes, he presents his diagnosis ofa variety of illnesses known to him, ranging frommeningitis and cancer to tuberculosis and gastrointes-tinal illnesses. In the fifth volume of this work, IbnSīnā offers an extensive discussion of pharmacology,providing a detailed description of the effects ofmedications on body.

Some of his observations are extraordinarily ad-vanced for his time. For example, he attributed the causeof plague to mice, commented on a number of conta-gious diseases, used single hair lines of horses forstitching after surgery, experimented with various drugsas anesthetics when operating on patients, describedsurgical processes for many operations such as gallbladder, used spices to stop bleeding after surgery, andunderstood the relationship between temperature andthe spread of diseases. He even experimented on animalsusing different drugs.

Ibn Sīnā’s treatment of the subject of psychologyas a science which is both independent and part ofthe field of medicine is extensive. He first argues for theexistence of a soul which is rather similar to theAristotelian psyche and then shows how this incorpo-real part of man interacts with his corporeal dimen-sion. Ibn Sīnā then goes on to say that the health of thebody to a large extent depends on the health of the souland he offers much elaboration on that point through-out his works.

Perhaps one of the most important contributions ofIbn Sīnā to the field of medicine is the technicalmedical terminology which he introduced and which isstill used by physicians in the Islamic countries.

PsychologyIn The Book of Healing, Ibn Sīnā treats the subject ofthe “three kingdoms” (minerals, plants, and animals).He extends the hierarchy of the incorporeal world to thematerial world, concluding that whereas each domainhas its soul it is only in humans that these souls reachtheir completeness. Ibn Sīnā’s treatment of the humansoul, its relationship with the body and the activeintellect, is extensive. He introduces five internalsenses and their equivalent five external senses.

The scope of Ibn Sīnā’s writings on sciences includessuch topics as motion, the process of sedimentation, andclassification of minerals in the Shifā ,˒ which came tobe known in the West as De mineralibus. In a famousdebate with al-Bīrūnī, Ibn Sīnā responded to ten ques-tions on Aristotle’s De Caelo and eight other questionssuch as how vision is possible, the relationship betweenwater and light, the nature of a vacuum, heat, cooling,and how it is that ice floats on water.

Ibn Sīnā’s philosophy remained the dominant philo-sophical school in the medieval west where he becameknown through translations of his works in Islamic SpainbyAvendeuth, whowas a Jewish philosopher andGerardof Cremona. The Sicillian school also benefited muchfrom Ibn Sīnā who was translated by Michael Scot. IbnSīnā’s works continued to be translated through thesixteenth century influencing such western philosophersas the Augustinian Gundisalvo, Alberttus Magnus,William of Auvergne, Alexander of Hales, Roger Bacon,and Duns Scotus.

Ibn Sīnā left an indelible mark on the history ofscience, medicine, and philosophy.

See also: ▶al-Kindī

References

Achena, Mohammad and Henri Masse, trans. Le Livre deScience. 2 vols. Paris: Les Belles Lettres, 1955–1958.

Anwaīi, G. C. Essai de bibliographie avicennienne. Cairo:Dar al-Ma‘arif, 1950.

Arberry, Arthur J. Avicenna on Theology. London: J. Murray,1951.

Avicenna, et al. The Canon of Medicine (Al-Qānūn Fī’l-t.ibb).Chicago, Illinois: Great Books of the Islamic World;Distributed by KAZI Publications, 1999.

Aziz, E., B. Nathan, and J. McKeever. Anesthetic andAnalgesic Practices in Avicenna’s ‘Canon of Medicine’.American Journal of Chinese Medicine 28.1 (2000):147–51.

Carra de Vaux, Bernard. Avicenne. Amsterdam: Philo Press,1974.

Corbin, Henry. Avicenna and the Visionary Recital. Trans.Williard Trask. New York: Pantheon Books, 1960.

Courtois, V., ed. Avicenna Commemoration Volume. Calcutta:Iran Society, 1956.

Ibn T. āwūs 1121

I

Dunn, Peter M. Avicenna (AD 980–1037) and ArabicPerinatal Medicine. Archives of Disease in ChildhoodFetal and Neonatal Edition 77.1 (1997): 75F–6F.

Gohlman, William E. The Life of Ibn Sīnā. Albany: StateUniversity of New York Press, 1974.

Goichon, A. M., trans. Le Livre des directives et remarques.Beirut: Commission internationale pour la traduction deschefs d’oeuvre, 1951.

Gruner, O. Cameron. A Treatise on the Canon of Medicine ofAvicenna. London: Luzac, 1930.

Hasnawi, Ahmad. The Definition of Motion in Avicenna’sPhysics. Arabic Sciences and Philosophy 11 (2001):219–55.

Jacquart, Danielle. Avicenne et la Nosologie galénique:L’Exemple des Maladies du Cerveau. Perspectives Arabeset médiévales sur la Tradition Scientifique et Philosophi-que Grecque. Ed. Ahmad Hasnawi, et al. Leuven: Peeters,1997. 217–26.

Jazi, Radhi and Farouk O. Asli. La pharmacopée d’Avicenne.Revue d’histoire de la pharmacie 317 (1998): 9–28.

Kâhya, Esin. One of the Samples of the Influence of Avicennaon Ottoman Medicine: Shams Al-Dīn Irāqī. Belleten (TürkTarih Kurumu) 64 (2000): 63–8.

Khan, M. S. Some Aspects of Ibn Sīnā’s ImportantContributions to Medical Science. Hamdard Medicus41.4 (1998): 19–25.

Krueger, Haven C. Avicenna’s Poem on Medicine. Spring-field, Illinois: C. C. Thomas, 1963.

Morewedge, Parviz. The Metaphysica of Avicenna ibn Sīnā.New York: Columbia University Press, 1973.

Nasr, Seyyed H. An Introduction to Islamic CosmologicalDoctrines. New York: Random House, 1978.

Nathan, B. and R. Wray. On the Causes and Collapse andSudden Death by Avicenna. International Journal ofClinical Practice 51.4 (1997): 245.

Rahman, F. Avicenna’s Psychology. London: Oxford Univer-sity Press, 1952.

Savage-Smith, E. The Practice of Surgery in Islamic Lands:Myth and Reality. Social History of Medicine 13 (2000):307–21.

Shah, Mazhar H. The General Principles of Avicenna’sCanon of Medicine. Karachi: Naveed Clinic, 1966.

Shah, S. B. Avicenna of Persia. American Journal of Otology20.1 (1999): 137.

Shahrastānī, Muhh.ammad ibn ‘Abd al-Karīm, et al. Strug-gling with the Philosopher: A Refutation of Avicenna’sMetaphysics. London: I. B. Tauris in Association with theInstitute of Ismaili Studies, 2001.

Strohmaier, Gotthard. Avicenna.München: C. H. Beck, 1999.

Ibn T. awus

ZEINA MATAR

Rad. ī al-Dīn Abū-l-Qāsim ˓Alī ibn Mūsā ibn Ja f˓ar ibnMuh.ammad ibn Ah.mad ibn Muh.ammad ibn T. āwūswas a religious scholar, historian, and astrologer. Hewas born in al-H. illa (Iraq) on 15 Muh.arram 589/21

January 1193. He belonged to a distinguished family ofscholars, the Banū T. āwūs, whose ancestry can betraced back to ˓Alī ibn Abī T. ālib.Ibn T. āwūs grew up in the town of al-H. illa, which

had been established by the famous scholar Abū Ja f˓aral-T. ūsī (385–458/995–1066) as a center of learningboasting five madrasas (institutions for the study of theIslamic sciences). Ibn T. āwūs spent his formative yearsin his native town, and in Baghdad where he lived for15 years. He made pilgrimages to the holy Shī ī˓ shrinesof Najaf, Kerbela, and al-Kazimayan. He had areputation for saintly powers, and concerned himselfextensively with popular religious practices.Ibn T. āwūs concentrated mainly on devotional lite-

rature, but he also wrote in the fields of history andastrology (see the listing of primary sources in thebibliography). In AH 650/AD 1252, he owned over1,500 volumes in his private library. ProfessorE. Kohlberg of the Hebrew University of Jerusalemhas contributed a superb reconstruction of this libraryand a detailed critical analysis of the works it contained.Ibn T. āwūs was one of the most prolific medieval

Shī ī˓ scholars, who aimed at providing the believerwith a set of guiding moral and ethical principles. Thesources stress his “erudition, knowledge, asceticism,devoutness, trustworthiness, understanding of fiqh(science, or knowledge), loftiness and godfearingness[along with his talents as] poet, man of letters, writer,and eloquent speaker” (Āghā Buzurg Tihrānī 1983). Aman of deep faith, concerned with religious matters,Ibn T. āwūs could also display wisdom in sensitivepolitical situations, as in this apocryphal story:

When Sultan Hulagu conquered Baghdad in 656/1258, heordered that the scholars give anopinion onwhich was preferable: the unbelieving but justsultan, or the Muslim despotic one. The scholarswere then gathered in al-Mustans.iriyya for thispurpose. They refrained from answering. Rad. īal-Dīn A˓lī Ibn T. āwūs was present at this Council.When he saw their hesitation, he took the futya( fatwa, legal opinion), and wrote that the unbeliev-ing but just ruler was preferable to aMuslim despot.

Although Ibn T. āwūs declined the office of Naqābat al-Ashrāf under the Caliph al-Mustans.ir (d. 640/1242), heapparently changed his mind during the MongolPeriod, and received the title from Nas.īr al-Dīn al-T. ūsī(d. 672/1273). This important office, which had ori-ginated under the Buwayhids (also Buyids, a dynastyin Persia and Iraq, 320–454/932–1062), enabledthe Sayyid families to represent their community inpolitical, religious, and scholarly matters.The date on which Ibn T. āwūs died in Baghdad is

generally accepted as 5 Dhū-l-qa d˓a 664/9 August1266, and he was probably buried in Najaf.

1122 Ibn Tibbon

References

Primary SourcesIbn T. āwūs. Kitāb al-Luhūf fī qat.lā al-t.ufūf. Tehran, 1904.---. Faraj al-mahmūm fī-ma r˓ifat nahj al-h. alāl wa-l-h. arāmmin i˓lm al-nujūm. Qum: Manshūrāt al-Rad. ī, 1944.

---. al-Malāh. im wa-l-fitan, 1963.---. Kashf al-muh. ajja. Tehran: Dafteri Nashri Farhangi Islāmī,1989a.

---. Kitab al-Yaqīn bi-ikhtis.ās. mawlānā A˓lī bi-imārat al-mu˓minīn. Beirut: Tawzī˓Dār al al-˓Ulūm, 1989b.

Secondary SourcesKohlberg, E. A Medieval Muslim Scholar at Work: Ibn T. āwūsand His Library. Leiden: Brill, 1992.

Matar, Zeina. The Faraj al-Mahmūm of Ibn T. āwūs: AThirteenth Century Work on Astrology and Astrologers.Ph.D. Dissertation, New York University, 1987.

---. Some Additions to the Bibliography of Mediaeval IslamicAstronomy from the Faraj al-Mahmūm of Ibn T. āwūs.Archiv Orientalni 57 (1989): 319–22.

---. Dreams and Dream-Interpretation in the Faraj al-Mahmūm of Ibn T. āwūs. The Muslim World 80.3–4(1990): 165–75.

Momen, M. An Introduction to Shi i˓ Islam. New Haven: YaleUniversity Press, 1985.

Strothmann, R. Die Zwölferschia: Zwei Religionsgeschich-tliche Charakterbilder aus der Mongolenzeit. Leipzig:Harrassowitz, 1926.

Ibn Tibbon

EMILIA CALVO

Ibn Tibbon, Jacob Ben Machir, is known as Profeit inRomance languages and as Prophatius Judaeus inLatin. These names come from the translation of mehir(prophet) into the languages of Southern France.

Ibn Tibbon was probably born in Marseille ca. 1236.His family was originally from Granada and, for fourgenerations, had been devoted to the translation ofArabic religious, philosophical, and scientific texts.Through these translations, Arabic learning and ther-efore Greek scientific traditions were made available tothe scholars of medieval Europe. Ibn Tibbon studiedmedicine at Montpellier and probably lived in Gerona,Spain between AD 1266 and 1267. He spent most ofhis life in Lunel, where his great-grandfather hadestablished and practiced medicine at the beginning ofthe twelfth century, and Montpellier where he died inAD 1305.

Ibn Tibbon translated works by Autolycus of Pitane,Euclid, Menelaus of Alexandria, Qust.ā ibn Luqa, Ibnal-Haytham, Ibn al-S.aff īr, Ibn al-Zarqāllu, al-Ghazālī,Jābir ibn Aflah. , and Ibn Rushd from Arabic intoHebrew.

He is also the author of some works dealing withastronomy:

Roba˓Yisrael (Quadrant of Israel), written betweenAD 1288 and 1293, in which an astronomicalinstrument, called the quadrans novus, is de-scribed. It consists of a simplification of the faceof the astrolabe. Some examples of this instrumenthave been preserved.

The Almanac, calculated forMontpellier and dated1 March 1300. It is based on Ibn al-Zarqāllu’sreelaboration of Awmātiyūs’ almanac, althoughthe author says that he has used the Toledan Tables,which is incorrect.

Ibn Tibbon is also the author of the Prologue toAbraham bar Hiyya’s Sefer Hesbon Mahlekot ha-Kokabim (Calculation of the Courses of the Stars).

References

Filius, L. S., ed. The Problemata Physica Attributed toAristotle: the Arabic Version of Hunain ibn Ishaq and theHebrew Version of Moses ibn Tibbon. Leiden: Brill, 1999.

Ibn Tibbon. Il quadrante d’Israel. Ed. and Trans. GuiseppeBofitto and C. Melzi d’Eril. Florence: Libreria Internazio-nale, 1922.

Millās, José María. Tractat de l ‘assafea d’Azarquiel.Barcelona: Universitat de Barcelona, 1933.

Poulle, Emmanuel. Le quadrant nouveau médiéval. Journaldes Savants (Apr.–June 1964): 148–67, 182–214.

Sarton, George. Introduction to the History of Science. Vol. 2.Baltimore: Williams & Wilkins, 1931.

Vernet, Juan. Ibn Tibbon. Dictionary of Scientific Biography.Vol. 8. New York: Charles Scribner’s Sons, 1976. 400–1.

Ibn T.ufayl

E. RUTH HARVEY

Abū Bakr Muh.ammad ibn ˓Abd al-Malik ibnMuh.ammad ibn Muh.ammad ibn T. ufayl al-Qaisi wasan Arab physician famous for his encyclopediclearning. He was born at Guadix in Granada (modernSpain) in the first decade of the twelfth century. Heserved local rulers as physician and diplomat, andeventually became the court physician to Abū Ya q˓ūbYūsuf, the Almohad prince who became the mostpowerful Muslim ruler of his day. Ibn T. ufayl enjoyed aclose friendship with Abū Ya q˓ūb until the latter’sdeath in 1184; he was esteemed and cherished by AbūYa q˓ūb’s successor, Abū Yūsuf Ya q˓ūb, until his owndeath in 1185–1186.

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Ibn T. ufayl’s importance for history is twofold: theinfluence of his unique work, H. ayy ibn Yaqz.ān, and hispatronage of one of the most important Muslimphilosophers of the Middle Ages, Ibn Rushd (knownto the west as Averroes). The medieval Arab historian,˓Abd al-Wāh. id al-Marrākushi, recorded that Ibn T. ufaylwould bring all sorts of learned men to his sovereign’snotice. It was in this way that Ibn Rushd was givenaudience with Abū Ya q˓ūb Yūsuf, and there was led onby the praise and encouragement of Ibn T. ufayl todemonstrate his familiarity with Aristotelian philo-sophical traditions. The Sultan himself joined in thediscussion, and Ibn Rushd was commissioned tocompose his great commentaries. It was through themediation of Ibn Rushd’s works that Aristotle wasreintroduced to the Latin West. The astronomer al-Bītrūjī (known in the West as Alpetragius) was adisciple and friend of Ibn T. ufayl; he mentions IbnT. ufayl’s criticisms of the traditional astronomicaltheories on epicycles and eccentrics.

Ibn T. ufayl was said to have written poetry as well asworks on medicine and astronomy, but nothing seemsto survive except H. ayy ibn Yaqz.ān and (possibly) apoem on medicine recently rediscovered (see Russell1986). The highly unusual H. ayy ibn Yaqz.ān (Life, Sonof Awareness) is a philosophical tale in the form ofa table: it tells how H. ayy, cast up as a baby orspontaneously generated on an island, is fostered by adoe and grows to adulthood without any human contactwhatsoever. Ibn T. ufayl’s interest lies in positing thenatural unfolding of the human reason from the blankof infancy to the highest possible intellectual develop-ment; H. ayy reaches the summit of human possibility ina mystical experience of the godhead. Eventually H. ayymeets another human being who is so filled with awe atH. ayy’s intellectual and spiritual attainments that hepersuades him to make an attempt to convert humansociety to wisdom. Humanity proves to be unworthy ofH. ayy’s teaching, and H. ayy and his new-found friendretreat back to the island again to spend the rest of theirlives in contemplation.

H. ayy ibn Yaqz.ān draws on the philosophy of IbnSīnā. It was edited as early as 1671 by Edward Pocock,who provided a Latin translation, thus inserting IbnT. ufayl’s ideas into the mainstream of European culture.The Philosophus Autodidactus, as Pocock named it,was sent to Huygens, Locke, and Leibniz; it waspossibly an influence on Defoe’s Robinson Crusoe, andalmost certainly one on Rousseau’s Emile. Englishtranslations have been appearing since 1686; there areDutch, German, French, Catalan, Hebrew, Persian, andRussian versions. It is still stirring up scholarly debateand controversy.

See also: ▶Ibn Rushd, ▶Ibn Sīnā

References

Conrad, Lawrence I., ed. The World of Ibn T. ufayl:Interdisciplinary Perspectives on H. ayy Ibn Yaqz.ān.Leiden: E. J. Brill, 1996.

De Vaux, Carra. “H. ayy b. Yak.z.an” and “Ibn T. ufayl”.Encyclopedia of Islam.New ed. Vol. 3. Leiden: Brill, 1971.

Gauthier, Léon. Ibn Thofail: Sa Vie, ses Oeuvres. Paris:Leroux, 1909.

Hawi, Sami S. Islamic Naturalism and Mysticism: APhilosophical Study of Ibn T. ufayl’s H. ayy bin Yaqz.ān.Leiden: Brill, 1974.

Ibn T. ufayl. Le Philosophe sans Maitre. Presentation deGeorges Labica, traduction de Léon Gauthier. Algiers:Société Nationale d’Édition et de Diffusion, 1969;Rpt. 1988.

---. H. ayy ben Yaqdhan, roman philosophique d’Ibn Thofail:traduction française. 2nd ed. Paris: Vrin, 1983.

Mallet, Dominique. Qui Enseigne Qui?: Lectures Du ‘H. ayyb. Yaqz.ān’ d’Ibn T. ufayl. Arabic Sciences and Philosophy8.2 (1998): 195–211.

Naseem, Hamid. Muslim Philosophy Science and Mysticism.1st ed. New Delhi: Sarup & Sons, 2001.

Nasri, Hani. The ‘Mystic’ and Society According to IbnBajjah and Ibn T. ufayl. International PhilosophicalQuarterly 26 (1986): 223–7.

Russell, G. A. The Role of Ibn T. ufayl: A Moorish Physician,in the Discovery of Childhood in Seventeenth-CenturyEngland. Child Care Through the Centuries. Ed. JohnCule and Terry Turner. Cardiff: British Society for theHistory of Medicine, 1986. 166–77.

Ibn Wafid

EMILIA CALVO

Ibn Wāfid Abū’l-Mut.arrif ˓Abd al-Rah.mān ibnMuh.ammad was a pharmacologist and physicist wholived and worked in Toledo during the first half ofthe eleventh century (ca. 1008–1075). He studied theworks of Aristotle, Dioscorides, and Galen in Cordobabut then he moved to Toledo where he planted abotanical garden for the king of this city, al-Ma˒mūn.Ibn Wāfid is the author of a book entitled Kitāb fī-l-

adwiya al-mufrada (Book on the Simple Medicines)which is a synthesis of Dioscorides and Galen. It is anextensive work to which the author devoted 20 years.It was abridged and translated into Latin by Gerard ofCremona. Translations into Catalan and Hebrew arealso extant.Ibn Wāfid is also the author of a pharmacopeia and

manual of therapeutics entitled Kitāb al-wisād fī ‘l-t.ibb(Book of the Pillow on Medicine) which, according toJuan Vernet, could be a misreading of the Arabic titleKitāb al-rashshād fi’l-t.ibb (Guide to Medicine). Thiswork can be considered complementary to the preceding

1124 Ibn Yūnus

one because Ibn Wāfid describes compound medicinesin it, and it is a practical book: the information given isbased on experience. Ibn Abī Us.aybi a˓ attributes to IbnWāfid a work entitled Mujarrabāt fī-l-t.ibb (MedicalExperiences) which could probably be identified withthis Book of the Pillow.

Ibn Wāfid is also the author of two works entitledTadqīq al-naz.ar fī i˓lal h.āssat al-bas.ar (Observationson the Treatment of Illness of the Eyes) and Kitābal-Mughīth (Book on Assistance) which are not preser-ved, andof a treatise on balneologywhich is preserved in aLatin version entitled De balneis sermo (Venice 1553).

Ibn al-Abbār attributes to Ibn Wāfid a book entitledMajmu˓al-Filāh. a (Compendium of Agriculture) althoughhis authorship is now being questioned.

References

Hopkins, J. F. P. Ibn Wāfid. Encyclopédie de l ‘Islam. 2nd ed.Vol. 3. Leiden/Paris: E. J. Brill/G. P.Maisonneuve, 1971. 987.

Ibn Wāfid. El libro de la almohada de Ibn Wāfid de Toledo(Recetario medico árabe del siglo XI). Ed. Camilo Alvarezde Morales. Toledo: Instituto Provincial de Investigacionesy Estudíos Toledanos, 1980.

---. Kitāb al-adwiya al-mufrada. Ed. Luisa Fernanda Aguirrede Cárcer. Madrid: CSIC–ICMA, 1993.

Samsó, Julio. Las Ciencias de los Antiguos en al-Andalus.Madrid: Mapfre, 1992. 267–70, 281.

Vernet, Juan. Ibn Wāfid. Dictionary of Scientific Biography.Vol. 14. New York: Charles Scribner’s Sons, 1976. 112–3.

Ibn Yunus

DAVID A. KING

Ibn Yūnus, Abu’l-H. asan ˓Alī ibn ˓Abd al-Rah.mān ibnAh.mad ibn Yūnus al-S.adaf ī was one of the greatestastronomers of medieval Islam. Unfortunately nothingof consequence is known about his early life oreducation. As a young man he witnessed the Fatimidconquest of Egypt and the founding of Cairo in 969. Inthe period up to the reign of Caliph al-˓Azīz (975–996),he made astronomical observations that were renewedby order of the Caliph al-H. ākim, who succeededal-˓Azīz in 996 at the age of eleven and was muchinterested in astrology. Ibn Yūnus’ recorded observa-tions continued until 1003.

Ibn Yūnus’ major work was a monumental zīj orastronomical handbook with tables. The H. ākimī Zīj,dedicated to the Caliph, is distinguished from all otherextant zījes by beginning with a list of observationsmade by Ibn Yūnus and others made by some of hispredecessors. Despite his critical attitude toward theseearlier scholars and his careful recording of their

observations and some of his own, he completelyneglects to describe the observations that he used inestablishing his own planetary parameters – nor doeshe indicate whether he used any instruments for theseobservations. Indeed, the H. ākimī Zīj is a poor source ofinformation about the instruments he used. In view ofthe paucity of this information, it is remarkable that thestatement that Ibn Yūnus worked in a “well-equippedobservatory” is often found in popular accounts ofIslamic astronomy. Sayili has shown how this notiongained acceptance in Western literature.

Ibn Yūnus’ Zīj was intended to replace the Mumtah.an Zīj of Yah.yā ibn Abī Mansūr, prepared for theAbbasid Caliph al-Ma˒mūn in Baghdad almost 200year earlier. When reporting his own observations, IbnYūnus often compared what he observed with what hehad computed using the Mumtah. an tables.

The observations he described are of conjunctionsof planets with each other and with Regulus, solarand lunar eclipses, and equinoxes; he also recordsmeasurements of the obliquity of the ecliptic (Chap. 11)and of the maximum lunar latitude (Chap. 38).

In spherical astronomy (Chaps. 12–54) Ibn Yūnusreached a very high level of sophistication. Althoughnone of the several hundred formulae that he presents isexplained, it seems probable that most of them werederived by means of orthogonal projections andanalemma constructions, rather than by the applicationof the rules of spherical trigonometry that were beingdeveloped by Muslim scholars in Iraq and Iran.

The chapters of the Zīj dealing with astrologicalcalculations (77–81), although partially extant in theanonymous abridgment of the work, have never beenstudied. Ibn Yūnus was famous as an astrologer and,according to his biographers, devoted much time tomaking astrological predictions.

Ibn Yūnus’ second major work was part of thecorpus of spherical astronomical tables for timekeepingused in Cairo until the nineteenth century. It is difficultto ascertain precisely how many tables in this corpuswere actually computed by Ibn Yūnus. Some appear tohave been added in the thirteenth and fourteenthcenturies. The corpus exists in numerous manuscriptsources, each containing different arrangements of thetables or only selected sets of tables. In its entirety thecorpus consists of about 200 pages of tables, mostof which contain 180 entries each. The tables aregenerally rather accurately computed and are all basedon Ibn Yūnus’ values of 30°0′ for the latitude of Cairoand 23°35′ for the obliquity of the ecliptic. The maintables in the corpus display the time since sunrise, thetime remaining to midday, and the solar azimuth asfunctions of the solar altitude and solar longitude.Entries are tabulated for each degree of both arguments,and each of the three sets contains over 10,000 entries.The remaining tables in the corpus are of spherical

Ibn Z. uhr 1125

I

astronomical functions, some of which relate to thedetermination of the five daily prayers of Islam. Theimpressive developments in astronomical timekeepingin fourteenth-century Syria, particularly the tables of al-Khalīlī for Damascus, also owe their inspiration to themain Cairo corpus.

It is clear from a contemporary biography of IbnYūnus that he was an eccentric, careless, and absent-minded man who dressed shabbily and had a comicappearance. One day in the year 1009, when he was ingood health, he predicted his own death in 7 days. Heattended to his personal business, locked himself in hishouse, and washed the ink off his manuscripts. He thenrecited the Qur ā˒n until he died – on the day he hadpredicted. According to his biographer, Ibn Yūnus’ sonwas so stupid that he sold his father’s papers by thepound in the soap market.

See also: ▶Yahyā ibn Abī Mans.ūr, ▶al-Ma˒mūn,▶al-Khalīlī

References

Primary SourcesMS Leiden Cod. Or. 143 and MS Oxford Hunt. 331 (majorfragments of al-Zīj al-kabīr al-H. ākimī). MS Paris B.N. ar.2496 (anonymous abridgment constituting the sole sourcefor some additional chapters).

MS Dublin Chester Beatty 3673 and MS Cairo Dār al-Kutubmīqāt 108 (complete copies of the Cairo corpus of tablesfor timekeeping).

Secondary SourcesCaussin de Perceval, A. P. Le livre de la grande tableHakémite. Notices et extraits des manuscrits de laBibliothèque Nationale 7 (1804): 16–240.

King, David A. The Astronomical Works of Ibn Yūnus. Ph.D.Dissertation, Yale University, 1972. (Available fromProQuest.com, no. 7229740.)

---. Ibn Yūnus. Dictionary of Scientific Biography. Vol. 14.New York: Charles Scribner’s Sons, 1976. 574–80.

---. Ibn Yūnus Very Useful Tables for Reckoning Time by theSun. Archive for History of Exact Sciences 10 (1973): 342–94. Rpt. in D. A. King. Islamic Mathematical Astronomy.London, 1986. 2nd rev. ed. Aldershot: Variorum, 1993. IX.

---. Synchrony with the Heavens: Studies in AstronomicalTimekeeping and Instrumentation in Medieval IslamicCivilization. Vol. 1: The Call of the Muezzin (Studies I–IX).Leiden: Brill, 2004; Vol. 2: Instruments of Mass Calcula-tion (Studies X–XVIII). Leiden: Brill, 2005.

King,DavidA. and Julio Samsó,with a contribution byBernardR. Goldstein. Astronomical Handbooks and Tables from theIslamic World (750–1900): An Interim Report. Suhayl:Journal for the History of the Exact and Natural Sciences inIslamic Civilisation (Barcelona) 2 (2001): 9–105.

Sayih, Aydin. The Observatory in Islam. Ankara, 1960. Rpt.New York: Arno Press, 1981. 130–56, 167–75.

Stevenson, F. R. and S. S. Said. Precision of Medieval IslamicEclipse Measurements. Journal for the History of Astron-omy 22 (1991): 195–207.

Ibn Z.uhr

MUNAWAR AHMAD ANEES

AbūMarwān ˓Abd al-Mālik ibn Z. uhr (Latin: Avenzoar;484–557/1092–1162) belonged to the Arabian tribeof lyād, Banū Z. uhr. His father, Abū al-˓Alā ibn Z. uhr(d. 525/1131), was a respected physician in the courtsof the Murābit. dynasty (482–541/1090–1147). Hetrained his son in the art and craft of medicine.Like his father, Ibn Z. uhr started his career in the

service of the Murābit. dynasty and earned a goodreputation. During the reign of ˓Ali ibn Tashfīn(499–537/1106–1143), he served at the palace inMarrakesh, Morocco, where his life was full of trialsand tribulations. In ca. 535/1141, he was stripped of hisofficial position and imprisoned. Although he waspardoned and released, he endured a hard life in prisonand the experience left a resentment in his heart againstthe ruling dynasty.The beginning of the reign of al-Muwāh.h. idūn

proved to be a blessing for Ibn Z. uhr. He was not onlyappointed as an official physician but also became awazīr in the court of Abū Muh.ammad ˓Abd al-Mūmin(d. 558/1163). During this period, Ibn Z. uhr transmittedhis knowledge and skills to his children with meticu-lous attention. His son and daughter both becamefamous physicians. One of Ibn Z. uhr’s treatises,al-Tadhkirah (The Remembrance), was dedicated tohis son in appreciation of his achievements.At least nine of Ibn Z. uhr’s works are known, but

only a few are extant. He is said to have writtentwo works and dedicated them to ˓Abd al -˒Mūmin.Al-Aghdhīyyah (On Dietetics) is a text on thetherapeutic properties of selected foods. Al-Tiryāqal-Sab ī˓nī is a book of antidotes against poisoning byenemies. This work, perhaps, was Ibn Z. uhr’s way ofexpressing gratitude to his benevolent patron.Al-Taysīr fī al-Mudāwāt wa al-Tadbīr (On Preventive

Regimen and Treatment), in 30 treatises, is consideredto be his monumental work. His friend Ibn Rushdconsidered it a great source of medical knowledge andtherapeutic advice. In its Latin version, Alteisir scilicetregiminis et medelae, the treatise remained in widecirculation across Europe for centuries. Both Arabic andLatin copies of this work are extant. True to the medicalnorms of his days, Ibn Z. uhr presented in this work amix of astrology and folklore blended with therapeuticsand pharmacology. Al-Kulliyāt (The Collection), ageneral compilation on medical practice, appears as anappendix.The great historiographer Ibn Abi ˓Us.aybi a˓h, in his

encyclopedic work ˓Uyūn al-Anbā fī T. abaqāt al-At.ibbā, listed only seven of Ibn Z. uhr’s works:

1126 Ibrāhīm Ibn Sinān

1. Fī al-Zīnah (On Beautification)2. Al-Tiryāq al-Sab ī˓nī (On Antidotes)3. Fī I˓lāl al-Kilā (On Diseases of the Kidney)4. Fī I˓llat al-Baras. wa al- B˒ahaq (On Leprosy and

Vitiligo)5. Al-Aghdiyyah (On Dietetics)6. Al-Tadhkirah (The Remembrance)7. Al-Taysīr fī al-Mudāwāt wa al-Tadbīr (On Preven-

tive Regimen and Treatment)

He does not mention two of his treatises. One of themissing ones is Al-Iqtis.ād fī Is. lāh. al-Anfūs wa al-Ajsād(Treatment and Healing of the Soul and Body).Addressed to the general reader, it focuses on problemsof hygiene and therapeutics. The second is Jāmi˓al-Asrār al-T. ibb (Compendium of Medical Wisdom).In addition to a discussion on dietetics, this workdescribes the physiology of several organs includingthe spleen, liver, and bladder.

Ibn Z. uhr was a prolific writer and a highly successfulmedical practitioner. Some of his work showed theinfluence of the Hippocratic and Galenic traditions, buthis original insights came from a rich family heritagein medical practice. Thus, going against the Greco-Roman medical dictates, Ibn Z. uhr engaged in experi-mental work and recorded his observations. His detailedstudy of the pericardial abscess, pharyngeal paralysis,intestinal and mediastinal tumors, and inflammation ofthe middle ear were great improvements over the workof his predecessors.

Ibn Z. uhr was one of the great Muslim clinicians andtherapists. Through numerous translations of his works,he remained highly influential in the medical acade-mies of the West. In his later age, he suffered from amalignant tumor that ultimately caused his death. Hewas buried in Seville, Spain.

See also: ▶Ibn Rushd

References

Arnaldez, Roger. Ibn Z. uhr. Encyclopedia of Islam, New ed.Leiden: Brill, 1969. 976–9.

Azar, Henry A. Ibn Zuhr (Avenzoar): Supreme in the Scienceof Medicine Since Galen: the Translation of His Work intoLatin and His Image in Medieval Europe. Ph.D. Disserta-tion, 1998.

---. Ibn Zuhr and Ibn Rushd: Friendship or Rivalry? Journalof the International Society for the History of IslamicMedicine (ISHIM) 1.1 (2002a): 11–5.

---. 1927 – When I Was Young… : Excerpts from Ibn Zuhr(Avenzoar)’s ‘Kitab al- Taysir’. Journal of the Internation-al Society for the History of Islamic Medicine (ISHIM) 1.2:(2002b): 21–6.

Azar, Henry A., Michael R. McVaugh, and JosephShatzmiller. Ibn Zuhr (Avenzoar)’s Description of aVerrucous Malignancy of the Colon: With an EnglishTranslation from the Arabic and Notes on its Hebrew and

Latin versions. Bulletin Canadien d’Histoire de laMédecine 19.2 (2002). 431–40.

Hamarneh, Sami K. Ibn Z. uhr. Dictionary of ScientificBiography: Ed. Charles C. Gillispie. New York: Scribners,1976. 637–9. Rpt. Health Sciences In Early Islam. Ed.Munawar Ahmad Anees. San Antonio, Texas: ZahraPublications, 1984.

Peña, Carmen and Fernando Girón Irueste. Medicina ‘versus’cirugía: el tratamiento de las enfermedades de los ojos enlas obras de Abulcasis y Avenzoar. Dynamis (Granada,Spain) 20 (2000): 163–87.

Puente, Cristina de la. Avenzoar, Averroes, Ibn al-Jatib,médicos de al-ándalus: perfumes, ungüentos y jarabes/prólogo de Paloma Díaz-Mas. Madrid: Nivola, 2003.

Wüstenfeld, F. Geschichte der Arabischen Aertze undNaturforscher. Göttingen, 1840. Reprinted Hildesheim:G. Olms, 1963.

Ibrahım Ibn Sinan

ROSHDI RASHED

Ibrāhīm Ibn Sinān Ibn Thābit Ibn Qurra was born inBaghdad in 296/909 where he died 37 years later in335/946. Grandson of the famousmathematician ThābitIbn Qurra, cousin of the famous literary figure Hilālal-S.ābi ,˒ son of a great physician and mathematicianSinān Ibn Thābit, he thus belonged to an intellectualaristocracy whose members frequented the corridors ofpower and the upper levels of the worlds of science andmedicine. Ibrāhīm was born into and raised in thisworld, before being the object of a short-lived persecu-tion to which he makes allusion but explains neither thecause nor the duration. Ibrāhīm Ibn Sinān was not onlythe “heir” to great tradition, but also a mathematician ofgenius in his own right who made his own mark on themathematics of his era.

Ibrāhīm Ibn Sinān was also heir to a historicaltradition. He belonged to a privileged generation, thefourth since the BanūMūsā. The translation of themajormathematical texts had been essentially completed andthe great traditions of research had already been wellestablished: that of the algebraists, beginning with al-Khwārizmī and extended by Abū Kāmil; that of thegeometers, al-Jawharī, al-Nayrīzī, etc., who followedthe work of Euclid; and the tradition of the Banū Mūsāwhich, thanks to mathematicians like Thābit Ibn Qurra,had already gathered considerable results, developednewmethods, and elaborated theories. Ibrāhīm Ibn Sinānwas clearly a part of this tradition in which Archimedeangeometry, a geometry of measurement, and the geometryof Apollonius, which was concerned with the propertiesof positions, were all combined. Profiting from scholarlyworks, especially those of his grandfather Thābit IbnQurra, Ibrāhīm Ibn Sinān developed the study of

Ibrāhīm Ibn Sinān 1127

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geometric transformations and their applications to conicsections, as well as to the measurement of the area of aportion of a parabola. He extended their work on sundialsin developing a theory of a whole class of instruments.Finally the questions posed by his predecessors aboutanalysis and synthesis prompted him to write the firsttreatise worthy of the name on the subject.

Ibrāhīm Ibn Sinān explained the composition of hiswork in his own autobiography which happily stillexists. He published the autobiography after his 25thyear, in 934. According to his own account, he beganhis research at age 15; at 16 or 17 he had written a firstversion of his book Fī Alāt al-az. lāl (On Instrumentsof Shadows), which he revised at the age of 25. A yearlater he was discussing and criticizing Ptolemy’sviews on The Determination of the Anomalies of Saturn,Mars, and Jupiter (Fī istikhrāj ikhtilāfāt Zuh. al waal-Mirrīkh wa al-Mushtarī ) in a treatise that he com-pleted 6 years later, at the age of 24. In geometry, IbnSinān wrote Fī al-dawā i˒r al-mutamāssa (The TangentCircles), al-Tah. līl wa l˒-Tarkīb (Analysis and Synthesis),Fī al-masaā i˒l al-mukhtāra (Selected Problems), Fīmisāh. at qit.˒ al-mah. rūt. al-mukāf ī’ (The Measurementof the Parabola), and the Fī rasm al-qut.ū˓ althalātha(Drawing of the Three Conic Sections). All these workshad been published and revised before Ibn Sinān was 25.

To illustrate the approach of Ibn Sinān let us lookbriefly at his Measurement of the Parabola, beginningwith what he wrote about his own studies:

My grandfather had determined themeasurement ofthis section. But several contemporary geometersledme tounderstand that awork of al-Māhānī on thesame subject, which they presented to me, waseasier than my grandfather’s. I was not pleased thatal-Māhānī’s work was more advanced than mygrandfather’s without there being one among uswho surpassed his work. My grandfather haddetermined his result in twenty propositions. Heproceeded from several arithmetic lemmas includedin the twenty propositions. The question of themeasurement of the section appeared to him clearlythrough the method of reductio ad absurdum. Al-Māhānī also proceeded from arithmetic lemmas. Hethen demonstrated his demand by the method ofreductio ad absurdum in five or six propositions,which involved lengthy discussions. I myself thendetermined the measurement in three geometricpropositions without recourse to any arithmeticlemma. I demonstrated the surface area of thissame section using the method of direct proof, andI did not need the method of reductio ad absurdum.

In addition to expressing pride in his heritage and thecertainty of an exceptional scholar, these remarks alsoreflect the qualities of Ibn Sinān as a mathematician:brevity, ease, and elegance.

Ibn Sinān’s approach is the following: in a firstproposition, he demonstrates that the affine transforma-tion conserves the ratios of the areas in the case oftriangles and polygons; he then demonstrates in a secondproposition that it is the same for the ratio of the area of aportion of a parabola to that of an associated triangle.Ibn Sinān again had recourse to geometric transfor-

mations in his Drawing of the Three Conic Sections. Inthis treatise, he constructed an ellipse by transformingthe circle by an orthogonal affinity – a process alreadyfound in the works of the Banū Mūsā. It was also bymeans of an affinity that he deduced all the hyperbolasof a particular hyperbola for which the latus rectum isequal to the transverse axis.The intensity of mathematical activity, the large

amount of work done, the new demands of brevity,elegance, and rigor in demonstration, as well as thegeneral interest in geometric transformations, all ledIbn Sinān to take up the theory of analysis andsynthesis again. Thus he published the first treatisedevoted to this subject. He wrote “I found that thegeometers of this time had neglected Apollonius’smethod of analysis and synthesis, as was the case forthe majority of things I brought up, and that they hadlimited themselves just to analysis, limiting themselvesto such a degree that they led analysis to the point ofletting people think that this analysis was not thesynthesis that they were doing.”In this treatise, Ibn Sinān undertook two tasks at

once: one didactic, the other logical. On the one hand,he proposed a method (t.arīq) for geometry studentswhich allowed them to solve geometry problems; onthe other hand, he reflected on geometric analysis itself,proposing a classification of geometry problemsaccording to their numbers and the hypothesis thatthey are to verify, and explaining for each class ofproblems the respective parts of analysis and synthesis.There is not enough space here to take up, even very

briefly, the works of Ibn Sinān. But the examplesdiscussed above do show how this eminent geometer lefthis mark on all the fields in which he worked, includingmathematics and philosophy. The import of his work canbe discovered in the work of Ibn al-Haytham whofollowedupon the researchof IbnSinān inhis own treatiseon analysis and synthesis and in his writings on sundials.

See also: ▶Banū Mūsā, ▶Thābit Ibn Qurra, ▶SinānIbn Thābit

References

Bellosta, Hélène. Ibrāhīm Ibn Sinān: On Analysis andSynthesis. Arabic Sciences and Philosophy 1.2 (1991):211–32.

---. Ibrahim Ibn Sinan: Apollonius Arabicus. Perspectivesarabes et médiévales sur la tradition scientifique et

1128 Ikhwān al-S.afā˒

philosophique grecque. Ed. Ahmad Hasnawi, et al.Leuven: Peeters, 1997. 31–48.

Ibn Sinan, Ibrahim, 880–943. Ibrahim Ibn Sinan: logique etgéometrie au Xe siècle. Ed. Roshdi Rashed, HélèneBellosta. Leiden: Brill, 2000.

Rashed, R. Ibrāhīm Ibn Sinān Ibn Thābit Ibn Qurra.Dictionary of Scientific Biography. Vol. VII. New York:Charles Scribners’ Sons, 1973. 2–3.

---. Les Mathématiques infinitésimales du IX e au XIe siècle.Vol. I. Fondateurs et commentateurs: Banū Mūsā, IbnQurra, Ibn Sinān, al-Khāzin, al-Qūhī, Ibn al-Samh. , IbnHūd.London: al-Furqān Islamic Heritage Foundation, 1995.

Rashed, R. R. Morelon and H. Bellosta. AstronomieGéométrie et Philosophie d’Ibn Sinān (Oeuvres Com-plètes) 2006 (in press).

Saidan, A. S. Rasā ī˒l Ibn Sinān (The Works of Ibrāhīm IbnSinān. In Arabic). Kuwait: Qism al-Turāth al-˓Arabī, 1983.

Suter, H. Abhandlung über die Ausmessung der Parabel vonIbrāhīm b. Sinān b. Thābit. Vierteljahrsschrift derNaturforschenden Gesellschaft in Zürich 63 (1918): 214ff.

Youschkevitch, A. P. Les mathématiques arabes. Paris: Vrin,1976.

Ikhwan al-S. afa˒

GREGG DE YOUNG

The 48 treatises composed by the Ikhwān al-S.afā˒(Brethren of Purity) constitute an encyclopedia of thesciences which has had a long and influential careerin Islamic civilization. The collection was prepared bya group of scholars who preferred anonymity. Thisanonymity has generated considerable debate amonghistorians over their identity. Current scholarshipplaces the date of composition in the last half of thefourth AH/AD tenth century, and the place of com-position in Basra. This collection of treatises continuesto play an important role in the intellectual milieu ofmodern Islam, especially among groups influencedby Shi i˓te and Ismā ī˓lī ideas.

The treatises contain a strong gnostic element, anemphasis on esoteric knowledge that exists within theexoteric or phenomenal features of everyday life but isaccessible only to the initiated. This interest in esotericor inner knowledge does not imply that they wereuninterested in the physical world. It is necessary tohave a thorough understanding of nature in order topenetrate to the inner truth that it expresses. An ap-preciation of nature, therefore, is one of the first stepstoward union with the Divine Knowledge.

Their gnostic orientation can be seen in the clas-sification of knowledge proposed by the Ikhwān. Thestudent beginswith introductoryor preparatory (riyād.iyy)topics, advances to religious (shar i˓yy) sciences, andfinally reaches the highest, or philosophic ( falsafiyy)sciences. This system is at odds with traditional Islamic

discussions of the arrangement of the sciences in thatit makes religious sciences subordinate to philosophicor intellectual sciences. In the organization of theirtreatise, the Ikhwān begin with mathematical sciences,advance to physical sciences, human sciences, andfinally to metaphysical and revealed sciences.

The gnostic tendencies of the authors appear in theNeo-Platonic and Neo-Pythagorean descriptions ofcosmogony and cosmology embedded within thesetreatises. God created the universe through a series ofemanations from himself. First to appear was Intellect,followed by its Archetypes and the World Soul. (Intel-lect, the Ikhwān tell us, instructs the World Soulthrough the Archetypes.) The World Soul, throughfurther emanations, produces individual souls orfaculties that individuate, or give form to, prime matter.The first of these individuating emanations werethe nine celestial spheres (the invisible primum mobile,the sphere of the fixed stars, and the spheres of theseven naked-eye planets: Saturn, Jupiter, Mars, Sun,Venus, Mercury, and the Moon), followed by the fourterrestrial elements (fire, air, water, and earth). Thisrepresents the farthest separation of soul from God.Drawn by an irresistible desire for union with the unityof God, it commences a return ascent heavenwardthrough a process of purification from the contamina-tion of matter achieved through personal morality anddeepening esoteric knowledge of the one.

The treatises contain little scientific information thatis new. The treatise on geometry (the second treatise ofthe collection) reports a few simple results from Euclid:the sum of the interior angles of the triangle is two rightangles, an exterior angle is equal to the two oppositeinterior angles, etc. However, there is no discussion ofthe demonstrations that validate these facts. Rather, theIkhwān are interested in facts only when related toother facts so as to provide insight into the deeper,esoteric, meanings of the knowledge. They discuss therelation between sensory and intellectual geometry. Thisis followed by a discussion of magic squares (numbersplaced in geometric arrays) and their almost magicalusefulness as talismans. Interspersed with these discus-sions are meditations on the usefulness of intellectualgeometry (because, abstracted from the sensations, itexercises the soul for moving beyond phenomenatoward the invisible one) and on the necessity forhuman cooperation and brotherhood in the effort.

Although the treatises provide little insight into thestate of intellectual activity in the sciences, they give anintriguing summary of what the educated non-scientistknew about the results of scientific research as theyexisted in that time. They also offer a window into whatmight be called a sub-scientific culture, a culture awareof some of the results of science and mathematics, butadapting these results for non-scientific (in this case,largely social and religious) purposes.

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References

Bausani, A. Scientific Elements in Ismā ī˓lī Thought: TheEpistles of the Brethren of Purity. Ismā ī˓lī Contributions toIslamic Culture. Ed. S. H. Nasr. Tehran: Imperial IranianAcademy of Philosophy, 1977. 121–40.

Brentjes, S. Die erste Risāla der Rasā i˒l Ih˘wān as.-S.afā˒ über

elemetare Zahlentheorie – ihr mathematischer Gehaltund ihre Beziehungen zu spätantiken arithmetischenSchriften. Janus 71 (1981): 181–274.

Diwald, S. Arabische Philosophie und Wissenschaft in derEnzyklopädie Kitāb Ih

˘wān as.-S.afā .˒ 3 vols. Wiesbaden:

Harrassowitz, 1975.Goldstein, B. A Treatise on Number Theory From a TenthCentury Arabic Source. Centaurus 10 (1964): 129–60.

Nasr, S. H. An Introduction to Islamic CosmologicalDoctrines. Cambridge: Harvard University Press, 1964.

De Young, G. Euclidean Geometry in Two MedievalEncyclopaedia. Al-Masāq 14 (2002): 47–60.

Ino Tadataka

NAKAYAMA SHIGERU

Ino Tadataka, 1745–1818, was a Japanese cartographerand an energetic field observer. A major astronomicaland geodetic problem of the time in Japan was findingthe length of a meridian by Japanese measure. SinceSino-Jesuit works had set zero longitude at Beijing, thatof Japan had to be accurately measured so that, inpredicting a solar eclipse, the Sino-Jesuit method couldbe employed for the Japanese longitude. After makingover 2,000 measurements of latitude, Ino calculated thelength of a meridian which agreed (within several tenthsof a second of a degree) with the figure given in theDutch translation of Lalande’s Astronomie which hadbeen imported into Japan.

He did not excel in devising new methods or newtheories in either astronomy or geodesy. While he wasactive, knowledge of Western astronomy was availablethrough Dutch translations and Sino-Jesuit works andafter, through the works of Lalande. But Ino had noknowledge of Dutch or dynamics and little understand-ing of astronomical theories. When calculating thelength of the meridian, he considered the earth as aperfect sphere rather than a spheroid. Moreover, whenobserving the position of fixed stars, he did not take intoaccount the effects of refraction, parallax, or nutation.

In his surveying, Ino did not usemodern triangulationbut relied upon the old traverse method. His mapmakingapproach resembled the Sanson–Flamsteed method (itis presumed that his method was developed indepen-dently), which is appropriate only for small areas.Ino none the less used the method for an area as large asall of Japan. Despite Ino’s scientific failings, his map

of Japan, based upon surveys covering the lengthand breadth of the land, has an important place ingeographical history.

References

Most of Ino’s works, consisting mainly of maps, observa-tions, records of his surveys, field notes, and diaries arepreserved in the Ino Memorial Hall in Sahara City.

Otani, Ryokichi. Ino Tadataka. Tokyo: Iwanami, 1932.

Inoculation

SUBHASH KAK

The first reliable account of inoculation is found in theeighteenth-century reports by British doctors concerningthe Indian treatment of smallpox. In themethod, believedto have been discovered sometime before AD 1000 inIndia (Henderson and Moss 1999), one deliberatelyinoculated, either into the skin or by nasal insufflation,scabs, or pustular material from lesions of patients. Thisresulted in an infection that was usually less severe thanan infection acquired naturally. From India, the practicespread to China, western Asia, and Africa and finally,in the early eighteenth century, to Europe and NorthAmerica.It appears that the idea of inoculation derived from

both agada-tantra, one of the eight branches oftraditional Āyurveda (Indian medicine) that deals withpoisons and toxins in small dosages, and from theapplication of specific concoctions to punctures in theskin for treatment of certain skin diseases (SuśrutaSamhitā in Cikitsāsthāna 9.10). The Caraka Samhitāspeaks of how deadly poisons can be converted intoexcellent medicine and how two toxins can be antagonis-tic to each other. The Samhitas speak of organisms thatcirculate in the blood, mucus, and phlegm. In particular,the organisms in theblood that cause disease are said to beinvisible.The Suśruta Samhitā, Chap. 54 of Uttaratantra or

Kāyacikitsātantra (General Medicine), suggests a treat-ment regimen that includes avoidance of fatty foods andsweets. In the Nidānasthāna (Diagnosis), Chap. 5, it isindicated that physical contact and sharing the same aircan cause such diseases to spread. Later, in Chap. 13,there is mention of the eruptive boils of the diseasemasūrikā. It appears that originally it meant chicken pox,but by the twelfth century the term was also being usedfor smallpox, as in the case of the commentator Dalhana.The best source concerning the Indian method of

treatment of smallpox is a report by Dr. John Z. Holwellin 1767 for the College of Physicians in London. This

1130 Inoculation

report is an excellent source for understanding the mindof the Ayurvedic doctor of the eighteenth century.

Holwell says that inoculators

are delegated for this service from the differentColleges of Bindoobund [Vrindavan], Eleabas[Allahabad], Banaras, &c. over all the distantprovinces; dividing themselves into small parties,of three or four each, they plan their travelingcircuits in suchwise as to arrive at the places of theirrespective destination some weeks before the usualreturn of the disease (Holwell 1971: 150–151).

One would presume that they were Ayurvedic vaidyas ortheir assistants.

They inoculate indifferently on any part, but if leftto their choice, they prefer the outside of the arm,midway between the wrist and the elbow, for themales; and the same between the elbow and theshoulder for the females. Previous to the operationthe Operator takes a piece of cloth in his hand,(which becomes his perquisite if the family isopulent) and with it gives a dry friction upon thepart intended for inoculation, for the space of eightor ten minutes, then with a small instrument hewounds, by many slight touches, about thecompass of a silver groat, just making the smallestappearance of blood, then opening a linen doublerag (which he always keeps in a cloth round hiswaist) takes from thence a small pledget of cottoncharged with the variolous [smallpox] matter,which he moistens with two or three drops of theGanges water, and applies it on the wound, fixingit on with a slight bandage, and ordering it toremain on for six hours without being moved, thenthe bandage to be taken off, and the pledget toremain until it falls off itself… The cotton whichhe preserves in a double callico rag, is saturatedwith matter from the inoculated pustules of thepreceding year, for they never inoculate with freshmatter, nor with matter from the disease caughtin the natural way, however distinct and mild thespecies.

The patient was to abstain from fish, milk, and gheebefore and after inoculation for a period of 1 month.Holwell claimed that when the inoculation regime wasstrictly followed, it is next to a miracle to hear that it“failed in one in a million.” He added that since

this practice of the East has been followed withoutvariation, and with uniform success from theremotest known times, it is but justice to conclude,it must have been originally founded on the basisof rational principles and experiment.

This is how Holwell described the explanations offeredto him by Ayurvedic vaidyas:

The immediate (or instant) cause of the smallpoxexists in the mortal part of every human or animalform; that the mediate (or second) acting cause,which stirs up the first, and throws it into a stateof fermentation, is multitudes of imperceptibleanimalculae [microorganisms] floating in theatmosphere; that these are the cause of allepidemical diseases, but more particularly of thesmallpox; that they return at particular seasons ingreater or lesser numbers… That these animalculaetouch and adhere to every thing, in greater orlesser proportions, according to the nature of thesurfaces they encounter; that they pass and repassin and out of the bodies of all animals in the act ofrespiration, without injury to themselves… small-pox is more or less epidemical, more mild ormalignant, in proportion as the air is charged withthe animalculae, and the quantity of them receivedwith the food (Holwell 1767: 155–156).

Holwell understood the idea behind inoculation in thismanner:

That when once this peculiar ferment, whichproduces the smallpox, is raised in the blood, theimmediate (instant) cause of the disease is totallyexpelled in the eruptions, or by other channels;and hence it is, that the blood is not susceptible ofa second fermentation of the same kind.

In other words, he believed that when the disease in itsnatural form or when introduced in its weak form by theinoculation had run its course, the patient was safe. Thedifference between these two forms was that in itsnatural course it is often fatal, whereas when introducedthrough inoculation, it was only an inconvenience.

It is significant that the spread of disease was takento be caused by the imperceptible animalculae (micro-organisms). This old insight of the Āyurvedic Samhitāswas a forerunner to the germ theory of disease thatarose in the nineteenth century.

References

Henderson, D. A. and B. Moss. Smallpox and Vaccinia.Vaccines. Ed. S. A. Plotkin and W. A. Orenstein.Philadelphia: W. B. Saunders Company, 1999.

Holwell, J. Z. An Account of the Manner of Inoculating forthe Smallpox in the East Indies. London: T. Becker andP. A. de Hondt, 1767.

Macgowan, D. J. Report on the Health of Wenchow for theHalf-Year Ended 31 March 1884. Shanghai: Chinese Im-perial Maritime Customs Medical Reports 27 (1884): 9–18.

Needham, J. China and the Origins of Immunology. HongKong: Centre of Asian Studies Occasional Papers andMonographs, University of Hong Kong, 1980.

Sharma, Priyavrat. Caraka-Samhitā.Varanasi: ChaukhambhaOrientalia, 1981–1985.

---. Suśruta Samhitā. Varanasi: Chaukhambha Visvabharati,1999–2001.

Iron pillar at Delhi 1131

Iron Pillar at Delhi

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R. BALASUBRAMANIAM

TheDelhi iron pillar (Fig. 1) is testimony to the high levelof skill achieved by the ancient Indian ironsmiths in theextraction and processing of iron. Hadfield (1912)undertook the first systematic scientific study of the Delhiiron pillar. Results of scientific studies conducted in 1961were summarized in a special issue of theNMLTechnicalJournal (vol. 5, 1963).A reviewof its corrosion resistanceappeared in 1970 (Wranglen 1970).WhileAnantharaman(1997) has reviewed the known scientific facts aboutthe Delhi iron pillar, Balasubramaniam (2002, 2005)has compiled several new insights into the historical,scientific, and technical aspects of the Delhi iron pillar.

The history of the pillar is revealed in the die-struckthree-stanza six-line Sanskrit inscription at a level ofabout 7 feet from the stone platform (Balasubramaniam2000a). King Chandra, mentioned in the inscriptionas the royal donor of this standarc for Vishnu, isprobably identical with Chandragupta II Vikramaditya(AD 375–414), as was also suggested by the use of thename “Chandra” on that king’s Archer-Type gold coins(Balasubramaniam 2000a). The original erection siteof this pillar was Vishnupadagiri (literally “hill of thefootprint of Vishnu”) as mentioned in the inscription.Vishnupadagiri is most probably identified withUdayagiri in central India, in the close vicinity of

Iron Pillar at Delhi. Fig. 1 Delhi iron pillar located inthe Quwwat-ul-Islam mosque in the Qutub Complex atNew Delhi.

Besnagar, Vidisha, and Sanchi (Balasubramaniam2000a; Dass 2001). The astronomical significance ofits erection site has been understood (Balasubramaniamand Dass 2004). The pillar was positioned so that theearly morning shadow of the pillar fell in the directionof one of the important bas-reliefs at Udayagiri, i.e., theAnantaśāyin Vishnu panel in Cave 13, in the periodaround the summer solstice. The chakra image thatoriginally crowned the iron pillar capital additionallyserved to highlight its astronomical significance(Balasubramaniam et al. 2004). The Delhi iron pillarwas relocated to its current location in New Delhi in thecourtyard of the Quwwat-ul-Islam mosque (near theQutub Minar) around 1233 AD by Iltutmish (Dass2001; Balasubramaniam 2002) (Fig. 2).

Engineering DesignThe current burial level of the pillar was not the originalburial level of the pillar when it was erected atUdayagiri. Hammer-marked cavities are still visible onthe surface of the pillar in the rough region just belowthe smooth surface-finish region (Fig. 3). The roughportion of the pillar was originally buried in the groundand later left exposed outside when the iron pillar wasrelocated at Delhi around 1333 AD. Beglar, an assistantof Alexander Cunningham, constructed the stoneplatform around the base of the iron pillar in 1871.A critical analysis of the dimensions of the main body

of the pillar allows an appreciation of the pillar’ssymmetrical design (Balasubramaniam 1997a). Therough surface occupies one-fourth (60U) and the smoothsurface three-fourths (180U) of the pillar main bodylength, excluding the decorative top (Fig. 4). Thedecorative bell capital (Balasubramaniam1998a) is againa symmetrical object. A chakra (circular discus) imagewas originally located atop the capital (Balasubramaniamet al. 2004) and this would have been approximately20U in length thereby making the total length of the

Iron Pillar at Delhi. Fig. 2 Well-preserved Sanskritinscription on the iron pillar. This is the oldest inscriptionon the pillar.

Iron Pillar at Delhi. Fig. 4 Relative dimensions of theDelhi iron pillar. The unit U measures 1 modern inch.

Iron Pillar at Delhi. Fig. 3 Hammer marked cavities arestill visible on the surface of the pillar in the rough region.The rough region was originally buried under the groundwhen the pillar was located at Udayagiri.

Iron Pillar at Delhi. Fig. 5 The Delhi iron pillar decorativecapital showing the discus image (chakra) that wasoriginally located at the top of the capital.

1132 Iron pillar at Delhi

decorative top 60U (Fig. 5). Therefore, the depth ofburial below ground level was equal to the height of thedecorative capital, indicative of the engineering designof the pillar. The unit U is equal to 1 modern inch.

Iron of Delhi PillarSeveral analyses of the Delhi pillar iron’s compositionare available (Table 1). The variation in the publishedcompositions and the high phosphorus content of theDelhi pillar iron must be noted. Compositional analysisnear the surface regions of a sample from the iron pillarrevealed that the composition of copper (0.05%), nickel(0.05%), manganese (0.07%), and chromium (Nil) wasuniform through several millimetres into the samplefrom the surface (Bardgett and Stanners 1963).

The presence of phosphorus is crucial to theatmospheric corrosion resistance of the Delhi ironpillar. The Delhi pillar iron contains a relatively largeamount of phosphorus compared to modern-day iron(produced in the blast furnaces). The relatively higherphosphorus content in ancient Indian irons is related tothe kind of slag that was created in the extractionprocess (solid-state reduction). Lime was not added inthe ancient Indian furnaces. The absence of calciumoxide in the slags leads to a lower efficiency forremoval of phosphorus from the metal, which invari-ably resulted in higher phosphorus contents in ancientIndian irons. Thermodynamic analysis of phosphorusremoval from iron in the absence of calcium oxide inthe slag also provides the same answer (Vikas Kumarand Balasubramaniam 2002).

Some aspects of the microstructure of the Delhi pillariron are also known. All the available published micro-structures have been described in Balasubramaniam(2003). It possesses a nonuniform grain structure andslag inclusions are irregularly distributed. Medium

Iron Pillar at Delhi. Table 1 Published composition analyses of Delhi pillar iron

Hadfield Ghosh Lahiri et al. Lal

(1912) (1963) Above (1963) Under (1963) (1996)

C – carbon 0.08 0.23 0.03 0.26 0.90Si – silicone 0.046 0.026 0.004 0.056 0.048S – sulfur 0.006 Trace 0.008 0.003 0.007P – phosphorus 0.114 0.280 0.436–0.48 0.155 0.174Mn – manganese Nil Nil Nil Nil NilN – nitrogen – 0.0065Fe – iron 99.720 Diff 99.67Others 0.246 0.011Specific gravity 7.81 7.672–7.747 7.5

Iron Pillar at Delhi. Fig. 6 Horizontal forge weldingtechnique for manufacture of the main body of the pillar.

Iron pillar at Delhi 1133

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to coarse polyhedral grains of ferrite with slip bandswere revealed in some grains near the surface. Thesurface regions were free from pearlite that seemed toincrease toward the interior. The absence of a uniformdistribution of pearlite is indicative of the segregationof phosphorus because, in such areas of phosphorussegregation, carbon diffuses out and the materialbecomes poorer in carbon content. The interior portionswere comparatively rich in carbon. Therefore, the Delhipillar iron exhibits a wide variation in structure and thisis also a characteristic feature of ancient Indian iron.

The pillar is a solid body with moderate mechanicalstrength (yield strength of 23.5 tons per sq. in., ultimatetensile strength of 23.9 tons per sq. in. and 5% elongation(Ghosh 1963)). The similarity of yield strength andultimate tensile strength are indicative of the compositestructure of the pillar iron. In fact, a cannonball fired atthe Delhi iron pillar in the eighteenth century (either byNadir Shah in 1739 or Ghulam Quadir in 1787) failed tobreak the pillar.

Manufacturing MethodologyThe pillar was manufactured using iron lumps and themethod used to fuse the lumps together was forgewelding. The individual iron lumps were extracted inbloomery furnaces. The likely manufacturing methodhas been deduced based on a critical analysis of variousaspects concerning the manufacturing methodologylike the hammering method, heating method, forgingmethod, use of inserts, use of dies and ease of handling(Balasubramaniam 1999a). The heated iron lumps wereplaced on the side surface of the pillar and hammeredon to the same by the use of hand-held hammers (Fig. 6).The addition of metal would have been sideways withthe pillar in the horizontal direction. The pillar’s verticaland horizontal movements would have been aidedby handling clamps provided on the surface of thepillar, the protruding portion of which must have beenchiseled away during the surface finishing operations.

Visual proof for the presence of these clamps has beendiscussed in detail elsewhere (Balasubramaniam 1999a).The decorative bell capital of the Delhi iron

pillar has been described in great detail elsewhere(Balasubramaniam 1998a). The decorative bell capitalconsists of seven distinct parts, excluding the circulardiscus that was originally atop the capital (Fig. 7).There are several evidences at the joints betweenmembers to indicate that lead solders were utilized forjoining the pieces together (Balasubramaniam 1998b,1999b). The bottom-most part is the reeded bellstructure, which has been manufactured by utilizingiron rods of uniform diameter. Atop this comes theslanted rod structure. The next three members arerounded structures, with the top one being only halfrounded because when the pillar is viewed from thebottom, this part would appear curved when viewed inperspective from the bottom. A round disc comesabove this and finally the box pedestal is placed on thetop of the capital. The box capital contains holes thatare empty at the four corners. The top of the pillarpresently contains a hollow slot (Fig. 8), in which a

Iron Pillar at Delhi. Fig. 7 The (a) top and (b) bottomportions of the decorative bell capital.

Iron Pillar at Delhi. Fig. 8 The top surface of thepillar capital presently contains a hollow slot.

1134 Iron pillar at Delhi

chakra image was originally fit (Balasubramaniamet al. 2004). As regards the fitting methodology,the seven components of the capital were shrunk fitaround a hollow cylinder, and this was joined to themain body of the pillar by means of a metallic insert(Balasubramaniam 1998a).

Corrosion ResistanceSeveral theories that have been proposed to explainthe superior corrosion resistance of the pillar can be

broadly classified into two categories: the environmentaland material theories. These theories have been criticallyreviewed elsewhere (Wranglen 1970; Balasubramaniam1997b, 2000b). The proponents of the environmenttheory state that the mild climate of Delhi is responsiblefor the corrosion resistance of the Delhi iron pillar,as the relative humidity at Delhi does not exceed 70%for significant periods of time in the year. It is knownthat atmospheric rusting of iron is not significant forhumidity levels less than 70%. On the other hand,several investigators have stressed the importance ofthe material of construction as the primary cause for itscorrosion resistance. The ideas proposed in this regardare the relatively pure composition of the iron used, thepresence of phosphorus and absence of sulfur/manga-nese in the iron, its slag enveloped metal grainstructure, passivity enhancement in the presence ofslag particles and formation of phosphate film. Othertheories to explain the corrosion resistance are also tobe found in the literature. They include the mass metaleffect, initial exposure to an alkaline and ammonicalenvironment, residual stresses resulting from thesurface finishing (hammering) operation, freedom fromsulfur contamination both in the metal and in the air,presence of layers of cinder in the metal which donot allow corrosion to proceed beyond the layer (cindertheory) and surface coatings provided to the pillarafter manufacture (treating the surface with steam andslag coating) and during use (coating with clarifiedbutter).

That the material of construction may be the importantfactor in determining the corrosion resistance of ancientIndian iron is attested by the presence of ancient massiveiron objects located in areas where the relative humidityis high for significant periods in the year (for example,the iron beams in the Surya temple at Konarak in coastalOrissa (Graves 1912) and the iron pillar at KodachadriHills on the western coast (Anantharaman 1999)).Moreover, a freshly exposed cut surface of the pillaracquires the color of the rest of the pillar in a relatively

Iron pillar at Delhi 1135

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short period of time (Balasubramaniam 2001), therebyimplying that surface coatings were not intentionallyapplied.

Sanyal and Preston (1952) proposed that the largemass of the pillar implies a large heat capacity forthe iron. In that case, the pillar would heat or coolfaster than the surroundings. The role of the Delhienvironment on the wetting and drying of the pillar hasbeen mathematically modeled (Halder et al. 2004) andthe benign role of the large mass of the pillar was noted.

Rust samples obtained from the region just belowthe decorative bell capital were characterized by X-raydiffraction (XRD), Fourier transform infrared (FTIR)spectroscopy, and Mössbauer spectroscopy (Balasu-bramaniam and Ramesh Kumar 2000). The XRDanalysis proved the existence of crystalline iron hydro-gen phosphate hydrate, FTIR and Mössbauer spectros-copy proved the presence of magnetite and severaloxyhydroxides in the amorphous form.

The process of protective film formation duringalternate wetting and drying cycles of the Delhi ironpillar has been outlined (Balasubramaniam 2000b) basedon rust characterization results. Initially, the corrosionof the matrix is relatively fast due to the presence ofsecond phase particles in the microstructure. The usualcorrosion products that are observed in the case of mildsteels exposed to atmosphere are generated: α-FeOOH(goethite), γ-FeOOH (lepidocrocite), Fe3−xO4 (magne-tite) and X-ray amorphous matter. The initial enhancedcorrosion of the matrix leads to the enrichment ofphosphorus concentration at the metal-scale interface,which results in the formation of a compact layer ofamorphous δ-FeOOH layer next to the metal-scaleinterface. The formation of this layer confers the initialcorrosion resistance to the pillar iron. Conversion ofamorphous δ-FeOOH to nanocrystalline goethite ispossible on longer exposure times (Yamashita et al.1994). The enrichment of phosphorus in rust continueswith prolonged exposure as observed in P-containingweathering steels (Misawa et al. 1974). Enrichment ofphosphorus follows the mesoscopic variation of phos-phorus in the matrix (Dillmann et al. 2002). Thisenrichment should be responsible for the precipitation ofthe insoluble phosphate, identified by XRD. Theformation of this phase at the metal-scale interfaceprovides further corrosion resistance.

A kinetic model for the growth of rust on the Delhiiron pillar has been proposed (Balasubramaniam 2002),based on the known nature and structure of the rust onthe Delhi iron pillar and other corrosion resistantancient Indian irons. According to this model, theinitial fast rate of corrosion is followed by a periodwhere the corrosion rate is reduced drastically. Growthrates have been roughly estimated for these two regionsbased on available Delhi iron pillar rust thicknessmeasurements (Balasubramaniam 2002).

The Delhi iron pillar is a marvel of ancient Indianmetallurgical skills. I have explained the engineeringdesign of the pillar followed by a description of themanufacturing methodology for the main body ofthe pillar. The characteristics of iron of the pillar andthe possible reason for its high phosphorus contenthave been discussed. The theories of corrosion resis-tance of the pillar have been reviewed and the impor-tance of the protective passive film mechanism hasbeen highlighted. The nature of this protective passivefilm has been addressed based on a detailed characteri-zation of its rust. The corrosion resistance of theDelhi iron pillar is due to both Delhi (with theenvironment providing alternate wetting and dryingconditions) and iron (with its high phosphorus contentconferring protection by the formation of a protectivepassive film).

AcknowledgementsThe author gratefully acknowledges the co-operation ofthe Archaeological Survey of India.

References

Anantharaman, T. R. The Rustless Wonder – A Study of theDelhi Iron Pillar. New Delhi: Vigyan Prasar, 1997.

---. The Iron Pillar at Kodachadri in Karnataka. CurrentScience 76 (1999): 1428–30.

Balasubramaniam, R. Studies on the Corrosion Resistance ofthe Delhi Iron Pillar. National Metallurgical LaboratoryTechnical Journal 37 (1995): 123–45.

---. New Insights on the Corrosion of the Delhi Iron PillarBased on Historical and Dimensional Analysis. CurrentScience 73 (1997a): 1057–67.

---. Mixed Potential Theory Analysis of the CorrosionResistance of the Delhi Iron Pillar. Transactions of theIndian Institute of Metals 50 (1997b): 23–35.

---. Decorative Bell Capital of the Delhi Iron Pillar. Journal ofMetals 50.3 (1998a): 40–7.

---. On the Presence of Lead in the Delhi Iron Pillar. Bulletinof Metals Museum 29 (1998b): 19–39.

---. Elucidation of the Manufacturing Technology Employedto Construct the Body of the Delhi Iron Pillar. Bulletin ofMetals Museum 31 (1999a): 42–65.

---. Some Aspects of Lead Presence in the Delhi Iron Pillar.Current Science 77 (1999b): 681–6.

---. Identity of Chandra and Vishnupadagiri of the DelhiIron Pillar Inscription: Numismatic, Archaeological andLiterary Evidence. Bulletin of Metals Museum 32 (2000a):42–64.

---. On the Corrosion Resistance of the Delhi Iron Pillar.Corrosion Science 42 (2000b): 2103–29.

---. The Protective Passive Film of the Delhi Iron Pillar.Bulletin of Metals Museum 34 (2001): 64–86.

---. Delhi Iron Pillar – New Insights. Shimla: Indian Instituteof Advanced Studies and New Delhi: Aryan BooksInternational, 2002a.

---. On the Growth Kinetics of the Protective Passive Filmof the Delhi Iron Pillar. Current Science 82 (2002b):1357–65.

1136 Irrigation in India and Sri Lanka

---. Effect of Material Inhomogeneity on Protective PassiveFilm Formation on Delhi Iron Pillar. Current Science 84(2003): 534–41.

---. Story of the Delhi Iran Pillar. New Delhi: FoundationBooks, 2005.

Balasubramaniam, R. and M. I. Dass On the AstronomicalSignificance of the Delhi Iron Pillar. Current Science 86(2004): 1134–42.

Balasubramaniam, R. and A. V. Ramesh Kumar. Characteri-zation of Delhi Iron Pillar Rust by X-ray Diffraction,Fourier Infrared Spectroscopy and Mössbauer Spectro-scopy. Corrosion Science 42 (2000): 2085–101.

Balasubramaniam, R., and M. I. Dass, E. M. Raven. TheOriginal Image atop the Delhi Iron Pillar. Indian Journal ofHistory of Science 39 (2004): 177–203.

Bardgett, W. E. and J. F. Stanners Delhi Iron Pillar – A Studyof the Corrosion Aspects. Journal of the Iron and SteelInstitute 210 (1963): 3–10.

Dass, M. I. Udayagiri-Rise of a Sacred Hill, Its Art,Architecture and Landscale – A Study, DeMontfort Univer-sity, Ph.D. Thesis, Leicestershire, UK, 2001. 92–155.

Dass, M. I. and R. Balasubramaniam. Estimation of theOriginal Erection Site of the Delhi Iron Pillar at Udayagiri.Indian Journal of History of Science 39 (2004): 54–71.

Dillmann, P., R. Balasubramaniam, and G. Beranger.Characterization of Protective Rust on Ancient Indian Ironusing Microprobe Analyses. Corrosion Science 44 (2002):2231–42.

Ghosh, M. K. The Delhi Iron Pillar and Its Iron. NationalMetallurgical LaboratoryTechnical Journal5 (1963): 31–45.

Graves, H. G. Further Notes on the Early Use of Iron inIndia. Journal of the Iron and Steel Institute 85 (1912):187–202.

Hadfield, R. Sinhalese Iron and Steel of Ancient Origin.Journal of the Iron and Steel Institute 85 (1912): 134–74.

Halder, S, G. K. Gupta, and R. Balasubramaniam. On theRole of Environment on the Corrosion Resistance of theDelhi Iron Pillar. Current Science 86 (2004): 559–66.

Kumar, V. and R. Balasubramaniam. On The Origin of HighPhosphorus Contents in Ancient Indian Iron. InternationalJournal of Metals Materials and Processes 14 (2002):1–14.

Lahiri, A. K., T. Banerjee, and B. R. Nijhawan. SomeObservations on Corrosion-Resistance of Ancient DelhiIron Pillar and Present-Time Adivasi Iron Made byPrimitive Methods. National Metallurgical LaboratoryTechnical Journal 5 (1963): 46–51.

Lal, B. B. The Delhi Iron Pillar: Its Art, Metallurgy andInscriptions. Ed. M. C. Joshi, S. K. Gupta, and ShankarGoyal. Jodhpur: Kusumanjali Publications, 1996. 22–58.

Misawa, T., K. Asami, K. Hashimoto, and S. Shimodaira. TheMechanism of Atmospheric Rusting and the ProtectiveAmorphous Rust on Low Alloy Steel. Corrosion Science14 (1974): 279–89.

Sanyal, B. and R. Preston. Note on Delhi Pillar. London:Chemical Research Laboratory, 1952.

Wranglen, G. The Rustless Iron Pillar at Delhi. CorrosionScience 10 (1970): 761–70.

Yamashita, M., H. Miyuki, Y. Matsuda, H. Nagano, andT. Misawa. The Long Term Growth of the Protective RustLayer Formed on Weathering Steel by AtmosphericCorrosion During a Quarter of a Century. CorrosionScience 36 (1994): 283–99.

Irrigation in India and Sri Lanka

CLAUDE ALVARES

Assessments by historians of Asia’s irrigation systemsand irrigation-related civil engineering techniques havebeen based on the scantiest of historical or empiricaldata. Naturally, they have ranged from one extreme tothe other. Of these, the one most easily recognized anddebated was provided by Karl Wittfogel whose theoriesled to the idea of “hydraulic civilizations”.

A diametrically opposite assessment has been providedby some Indian historians who have concluded thatthere was no significant irrigation technology in useat all. Symbolic of this view is R. Majumdar andH. C. Raychaudhuri’s An Advanced History of India,in which the authors make a categorical statement onthe “comparative absence of artificial irrigation” ineighteenth century India.

However both views – fairly representative of thehistoriographical terrain – have had to be revisedconsiderably because of the emergence of new historicalmaterials and investigations. These are reflected in newliterature specifically devoted to the subject. Illustrativeof these materials is the report of Alexander Walker, anEnglish specialist who toured India in the eighteenthcentury. Walker produced an elaborate treatise on Indianagriculture in which he drew the conclusion that:

the practice of watering and irrigation is notpeculiar to the husbandry of India, but it hasprobably been carried there to a greater extent, andmore laborious ingenuity displayed in it than inany other country.

This display of ingenuity, however, is not restricted toeighteenth century India and has indeed foundexpression in a plethora of irrigation systems in Asiaeach designed to appropriate its own specific ecosys-tem potential. There is evidence of large-scale irriga-tion works in several Asian countries including Chinaand Sri Lanka. The systems studied on the subcontinentinclude gigantic artificial lakes, large-scale and small-scale embankments, and diversion channels. Theyinclude schemes for taking water up a hill againstgravity, elaborate canal distribution networks, innova-tions like the khazans on the west coast of India, whereunmanned wooden sluice gates control the sway of saltand sweet water in low-lying paddy fields adjoiningthe coastal or tidal rivers, and storage tanks with abewildering variety of names.

“The irrigation history of Indian has been studiedonly in fragments” (Sengupta 1993). But even thisadmittedly fragmentary picture that is emerging is

Irrigation in India and Sri Lanka 1137

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far more fascinating than the simplistic or impression-istic scenarios of Wittfogel or later historians likeRaychaudhuri and Majumdar. The most fundamentalaspect of irrigation technology and civil engineeringworks to be noted is that almost all of them are relatedto monsoon precipitation in one way or another. Over90% of the annual runoff in the peninsular rivers and80% in the Himalayan rivers occur during the 4 monthsof the monsoon. Thus, unlike the case of temperateecosystems, irrigation becomes extremely crucial: inthe wet seasonwhich stretches approximately 4months,in several places less, there can be too much precipita-tion over intense bursts. This is followed by a dry seasonduring which there is no precipitation at all. The resultis predictable: periods of excess water followed bydrought.

In this context, the basic design of irrigation techno-logy is intimately related to precipitation: how to save it,store it, and divert it, so that spatially it reaches areaswhere there is no water (diversion techniques) ortemporally makes it available during the dry months(storage techniques). Thus, rain-fed rivers are divertedinto channels, or river basins are interconnected. Or therainfall is directly collected in huge storage facilities onthe land.

If this is the scenario (and it is as valid today as it wasin 3000 BCE), one would normally expect a muchricher history of irrigation techniques in Asian condi-tions – where rice is a basic crop adapted to growinglargely in water – than in any other part of the planet,particularly the temperate zones. It would also followthat the irrigation designs evolved for coping with suchsituations would not readily be available in otherecosystems. For this reason, it has taken some time forengineers and historians trained in other culture areas toappreciate their worth and function.

The irrigation experience of China is documented inJoseph Needham’s magnum opus, Science and Civili-sation in China, and will not concern us here. We shallrestrict ourselves in this essay to a consideration of theirrigation and civil engineering techniques that arose inthe Indian subcontinent including Sri Lanka and whichwere the result of a close interaction and adaptationbetween overall environmental situations and humaningenuity.

Irrigation TechnologiesIn the circumstances related above, it stands to reasonthat the primary design objective of irrigation engineerswould be predominantly in the direction of a waterstorage system. The following listing is given byShankari and Shah.

There were storage systems designed purely fordrinking water: nadi, tanks, bowari, jhalara, and

pokhar. Some were reserved only for human beings;others were for human beings and animals. These weshall ignore here.The second category of storage technologies relates

to irrigation, and there is considerable evidence of thespread of such technologies through the length andbreadth of the subcontinent. Though the structures herewere all designed for irrigation, they also providedother useful functions of soil conservation and groundwater percolation and recharge.Irrigation water stored in such storages was con-

veyed through two methods: first, under the force ofgravity, or gravity irrigation, and second, throughextractive or lift techniques or devices of some kind,including for instance the Persian wheel.Therewere threemainclasses of such irrigation-related

storage systems. The first comprised tank and pondirrigation systems. These in turnwere of two types:abovesurface storage works, where a reservoir was createdabove the ground through a fairly long embankment. Thecorresponding structures were called Keri, Eri, Cheruvu,Kalvai, and Kunta in South India and Ahar in Bihar(northern areas). The second category involved belowsurface storage works, which included dug ponds fromwhich water was lifted by some means manual ormechanical: pokhar, talab, jhil, beel, and sagar.The second class of irrigation systems comprised

land inundation systems: the land was flooded andsaturated before cultivation and then drained off priorto planting (another term used is flood irrigation).These were primarily above surface types or referred to(in India) as submergence tanks. Important variationsof these are the khadin and the johad in Rajasthan andthe bundhies of Madhya Pradesh.The bundhies were built generally in a series and

therefore captured every possible drop of rainwater thatfell. If there were a surplus, a waste weir was provided.There was generally a sluice at the deepest part of thestorage reservoir. A stambh or pillar would indicate thelocation of the sluice. Sluices could be of differenttypes: pipe sluices or sluices made of masonry for thelarger tanks. (Some sluices open, as in the khazans,with the pressure of the incoming tides and dischargewater automatically when the tide has fallen; these aremade from wood.) The crop which was grown inthe bundhies after the water was drained did not requireany irrigation until harvest.The third class comprised in situ techniques through

which storage facilities were created to retain precipi-tation and ground water infiltration. The differencebetween classes 2 and 3 was that in the former,cultivation followed drainage; in the latter it occurredsimultaneously.The sizes of these storage tanks varied and the tanks

themselves were generally known from the command

1138 Irrigation in India and Sri Lanka

areas they irrigated: the smallest ones irrigated around50 acres, the medium ones about 100, and the majorones 500 and above. The large tanks were clearlyimpressive in scale. The Veeranam Tank in Tamil Naduhas a bund (embankment) 16 km in length. TheGangaikonda Cholapuram tank, also in Tamil Nadu,was constructed by a Chola king from AD 1012 to 1044and survives even today with a 25 km embankment.

The construction of tanks was a widely dispersedskill. To create a tank reservoir, an earthen embank-ment, usually curved, was erected in a concave formacross the flow of water. The water was retained inthe belly of the curve from where it was drawn anddirected through channels to irrigate plots at lowerlevels through gravity irrigation. After the tank wasemptied, the tank bed itself could be used temporarilyfor raising a crop utilizing residual moisture. Many ofthe tanks in an area were interlinked and functioned asparts of an integrated system. The tank at the higherlevel released its surplus water as runoff to tanks at alower level and the next in turn. These were calledchain tanks. There were also tanks which were fed bycanals from a river. Chain tanks were generally createdin the upper reaches of the river basin and river-fedtanks in the lower reaches. Their construction wouldhave required detailed cooperation among severalcommunities in the region.

In Mysore in 1866 Major R. H. Sankey, ChiefEngineer, wrote:

Of the 27,269 square miles covered by Mysore,nearly 60% has, by the patient industry of itsinhabitants been brought under the tank system.Unless under exceptional circumstances, none ofthe drainage of these 16,287 square miles isallowed to escape. To such an extent the principleof storage has been followed, that it would nowrequire some ingenuity to discover a site withinthis great area suitable for a new tank.

The profusion of such tanks was not a feature ofKarnataka alone. Experience was similar in TamilNadu, Goa, or Bihar. The area north of the Vindhyamountain range in middle India for instance had morethan 8,000 submergence tanks. In one district ofRajasthan alone, there were more than 500 khadins.

In Sri Lanka, dry areas were populated with what areknown as “tank villages”. “The one-mile to an inchtopographical maps of the island,” writes D. L. O.Mendis:

show nearly 15,000 of these, of which over 8000are in working condition today. Tradition has itthat some 30,000 of these small tanks had beenconstructed down the ages and there is a referencein the chronicles to 20,000 in the ancient provincealone in the 12th century.

Water ConveyanceApart from the storage works, the subcontinentwitnessed the emergence of competent and impressivewater conveyance systems designed to divert waters ofrivers and flowing streams. Some diversions wereaccomplished without a check or embankment acrossthe river; in such instances, the flood waters of the riverwere drained through a natural diversion. The Kuhls orGuls in the Himalayan areas, the dongs of theNortheastern states, and the pynes of Bihar all reflectthis feature.

The second category involved check dams as a basicfeature: the river bed was first raised and the resultingraised water diverted into a channel as was the casewith the band-haras. Some of these schemes werefairly small, like those in the hilly areas. Others couldbe extremely large-scale and it is the reports of the latterthat probably gave Wittfogel material for his specula-tions. According to Major T. Greenway, these wereworks of “truly gigantic magnitude, vast embankmentsand drainage channels equal to ordinary English riversin capacity.”

Historical Development of Irrigation TechniquesThe interesting question that is now being asked iswhether one can talk in terms of an evolution ofirrigation technologies and civil engineering techniquesfrom the earliest times to the present? The question isimportant in view of the fact that many of these storagesystems, diversion channels, and embankments arelargely intact and still in use. There are still parts of thecountry where Persian wheels are operated. Tanks andstorage vessels are once again being made functionaland weirs continue to be constructed.

The answer seems obvious: while more complextechnological mechanisms did emerge as time passed,the earlier and the later techniques have continued tocoexist. The only major new innovation seems to be theidea of dams; these are new in terms of function, sincethe generation of hydropower was not intended inearlier times. The idea of large dams, once consideredthe temples of modern India, has taken a severe beatingin recent years. They are now considered unsuited totropical ecosystems, since the reservoirs invariably leadto displacement of large numbers of people, sub-mergence of forests, and destruction of wildlife, andin places like Sri Lanka, submergence of smallerfunctioning reservoirs.

This being said, it is possible still to identify certainperiods as distinct historical events in a possible historyof irrigation and civil engineering on the subcontinent.There is archeological evidence of artificial irrigationfrom pre-Harappan and Harappan times (ca. 5500–3500 BCE): this took the form of a large number

Irrigation in India and Sri Lanka 1139

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of wells. One well found had a brick lining goingdown 12 m. Post-Harappa, the major irrigation find isInamgaon on the west coast of India where under theinfluence of the Jorwa culture (ca. 3400–3000 BCE),one finds evidence of a major diversion schemereflected in a massive embankment 240 m by 2.2 mwide to divert the river into a channel. The channelitself was 200 m long and 4 m wide.

The first storage tanks in their rudimentary formappear around 2500 BCE – also in Sri Lanka –with theinvention of iron tools. Hereafter, there are increasingreferences in literary works of both Sanskrit and Tamilup to the Gupta (AD 350) period. There are tank-relatedinscriptions which give details of tank construction,maintenance, sources of funds for maintenance, and soon. The word eri also comes into circulation by theseventh century as a term for tanks.

The anicut (weir) technique is probably older thanthe eri or tank. The most famous of the anicuts, theKaveri Anicut on the river Kaveri, is linked to a Cholaking of the second century AD. It involved a dam onthe river Kaveri 300 m long and 12–18 m wide and 5 mdeep. There is a dispute about the age of the anicut,since the anicut technique itself bears a strong resem-blance to the Sri Lankan technique of massive stonedams and sluices, a technique which developed, accord-ing to Sri Lankan historian R. A. L. H. Gunawardene,only in the seventh century AD.

Sir Arthur Cotton paid eloquent testimony to theengineering talent involved in the large-scale irrigationworks. He wrote:

There are a multitude of old native works invarious parts of India… These are noble works,and show both boldness and engineering talent.They have stood for hundreds of years… it wasfrom them that we learnt how to secure afoundation in loose sand of unmeasured depth.In fact, what we learnt from them made thedifference between financial success and failure,for the Madras river irrigations executed by ourengineers have been from the first the greatestfinancial successes of any engineering works inthe world, solely because we learnt from them…With this lesson about foundations, we builtbridges, weirs, aqueducts, and every kind ofhydraulic work… we are thus deeply indebted tothe native engineers…

Social Arrangements/Religious SanctionA significant feature of these irrigation works related totheir construction and maintenance. Since wateravailability could be problematic with monsoon failure,those associated with the emergence of these workscould gain religious merit for their deed. Though largesystems were often sponsored by the state – to include

kings, queens, local chieftains, zamindars (land-owners) – village communities, temples, and evenindividuals are associated with their construction. Thusa public park in Pondicherry bears an inscriptionrecording a tank built by a dasi – a temple dancer/courtesan –while another inscription in Karnataka (AD1100) records a tank and shrine constructed by a villagewatchman.All the major dynasties including the Mauryas

(Sudarshan Lake near Kathiawar), the Cholas, theHoysalas, and the Vijayanagar Kings and MuslimSultans were associated with irrigation works. Of these,the most impressive schemes are associated with theCholas. However, these kings depended upon a cadreof skilled hydraulic engineers. Dikshit records theperformance of one such engineer in the fourteenthcentury:

The Kalludi (Gauribidanur taluk) inscription of1388 AD is well known. According to it, whenVira Harihara Raya’s son Sri Pratapa Bukkarayawas in Penugonda city in order that all the subjectsmight be in happiness – water being the life of theliving beings – Bukkaraya in open court gave anorder to the master of ten sciences, the hydraulicengineer (Jalasutra) Singayya Bhatta that he mustbring the Henne (Pennar) river to Penugonda.Accordingly Singayya Bhatta conducted a chan-nel to the Siruvara tank and gave the channel thename Pratapa Bukka Raya Mandalanda Kaluve.

The day-to-day operation and maintenance of bothlarge and small works were mostly in the hands of localcommunities and of special professionals like thenirkattis of Tamil Nadu. In many areas, productionfrom certain lands was set aside specifically to meet themaintenance costs of tanks. During the installation ofthe colonial regime, these revenues were appropriatedby the colonial power and consequently the mainte-nance of such irrigation works fell into bad timesleading to declines in efficiency.

References

Dharampal. Indian Science and Technology in the 18thCentury. Delhi: Impex India, 1983.

Dikshit, G. S., G. R. Kuppuswamy, and S. K. Mohan. TankIrrigation in Karnataka: A Historical Survey. Bangalore:Gandhi Sahitya Sangha, 1993.

Majumdar, R. C. and H. C. Raychaudhuri. An AdvancedHistory of India. 3rd ed. London: Macmillan, 1967.

Mendis, D. L. O. Lessons from Traditional Irrigation andEco-Systems. The Revenge of Athena: Science, Exploita-tion and the Third World. Ed. Ziauddin Sardar. London:Mansell, 1988. 317.

Needham, Joseph. Science and Civilisation in China. Cam-bridge: Cambridge University Press, 1954.

Sengupta, N. User-Friendly Irrigation Designs. New Delhi:Sage Publications, 1993.

1140 Irrigation in the Islamic world

Shankari, U. and E. Shah. Water Management Traditions inIndia. Madras: PPST Foundation, 1993.

Somashekhar, R. Forfeited Treasure: A Study on the Status ofIrrigation Tanks in Karnataka.Bangalore: Prarambha, 1991.

Wittfogel, Karl A. Oriental Despotism: A Comparative Studyof Total Power. New Haven, Connecticut: Yale UniversityPress, 1957.

Irrigation in the Islamic World

LUCIE BOLENS

From Andalusia to the Far East, from the Sudan toAfghanistan, irrigation in Islamic countries is the basisof all agriculture and the source of all life. After theRoman empire, the classical Islamic empires reliedon the great cities like Damascus, Baghdad, Cairo,Cordoba, and Fez. In the countryside, all the smallvillages, made up of groups of rush huts or houses ofstone, wood, or concrete were organized around a watersource: a mountain fed by a living spring, a cistern ofrain water, or wells bringing water up to the surfacefrom deep beds. The Arabic word for water,Mā ,˒ is alsothe word for center. The water for religious ablutions atthe center of the courtyard facing every mosque is thesymbolic echo of a physical fact.

Islamic irrigation recovered pre-Islamic purviewswhile at the same time developing and expanding them.The historical record describes a vast network of canalsfrom hot climatic zones to cold, rainy ones. The firstwere developed in the river valleys of semiarid and aridregions. The Nile, the Tigris and Euphrates, and theGuadalquivir have offered rural and urban commu-nities from earliest times both water and silt, a means ofproviding refreshment and nourishment.

Where no great rivers existed, human societies dugwells and prospected deep lying aquifer beds, in thesouth of the Arabian peninsula, in Yemen, and inHadramawt, as well as in the Sudan. There, where theeffects of Indian monsoons are often felt, a tropicalagriculture (coffee trees, date palms, banana, andtamarind trees) served as a point of departure for thosetropical plant species to Mediterranean regions.

Lastly, on the borders of agricultural zones stretchedvast steppes with winter rainfalls varying from 50 to150 mm per year, seminomadic lands which had beenused for thousands of years. Animal husbandry andintensive agriculture at oasis sites have for centuriescontributed to the economic base of Yemenites andMaghreb tribes. This association between seminomadicgrazing and intensive irrigated agriculture is a distinc-tive characteristic of Islamic irrigation, a system of acomplementary nature between field, pasture, andnatural resources in the environment.

For classical Islam, written documentation is insepa-rable from the latest results of rural archeology; allof the Kitāb-al-Filāh. at (Books of Agriculture) –Maghrebian, Andalusian, Egyptian, Iraqi, Persian, orYemenite – insist meticulously on the deployment ofequipment and on the control of water. What areexamined are the means of water distribution, follow-ing the season and the species being cultivated. ATribunal of Waters looks at legal cases, and that of theIslamic writer Valence has lasted from the time ofthe Christian Reconquista in 1248 until today. Irriga-tion was linked to a social time, following necessities ofnature but also following the social rank of the users.

In the current state of research, one of the oldestcalendars of irrigation was found in the Filāh. atal-Nabat.iyyah (Nabataean Agriculture, by Ibn Wah.shiyyah), which in the 1000s gave information on pre-Islamic Mesopotamia and Abbasidian Iraq. For westernIslam, jurisprudence provided historians with precisedetails of daily life and ecological behavior, andexplained the elements relating to the history of thatenvironment, such as torrential rains in the autumn andthe spring, the shifting of waterholes, and complaintsfrom the owners of cultivated estates which had beendeprived of water from one day to another. The fiqhIslamic juris, had to regulate any unexpected eventsfrom case to case. The joint purchase of land and water,inherent to the fiqh, confronted the fact of the capricious-ness of nature: the agrarian weather of microclimatesreally was the final law. In Islamic law ownership of landis always linked to ownership of waters.

Lastly, financial writings integrate the agrarian depen-dence on water into the framework of the whole politicaland social evolution of Islamic history. Irrigation is thecrucial element of agriculture in Islamic lands.

The rains follow two dominant climatological pat-terns: one Mediterranean, the other tropical and sub-tropical. The Mediterranean basin, along with southernAfrica and California, has the only climate which hasrain in the winter and maximum heat in the summer. Thevegetation there needs a hot, humid season in its tillagephase. In other respects, the torrential spring and autumnrains create a major risk for the thin, mountainoussoil which is predominant in the Mediterranean basin. Anegative quality can thus indeed have positive effects.

This link between the climate and the soil inAndalusia entailed three inseparable factors: an ex-tremely fragile ecology at risk of erosion, a highlyorganized and detailed system of irrigation which wasadapted to regional conditions, and a stable politicaland administrative system (except in time of war).

In certain historical cases, like that of Andalusia, inspite of the fluctuating tides of conquest and recon-quest, there existed a true ecological pattern whichlasted for several centuries and which served as a realecological laboratory for eastern and western Islamic

Irrigation in South America 1141

I

statutes, based on a high level of natural science,climatology, and botany. The extensive spread oftheoretical and technical knowledge made of theAndalusian model a precedent which could be appliedto all societies, ethnic, and religious differences aside,which were trying to understand the environment in itshistorical dimension.

It was water which governed the classification ofland types. The rich agronomical and administrativeliterature of Arabic Islam divided cultivatable land intorainy land and irrigated land. The former were thoselands which received enough winter rain to permit thecultivation of olive trees, grape vines, and citrus trees,the Mediterranean trilogy. Irrigated plantings usedwater stored in deep beds; the surface of the land washot and irrigated and was worked in squares irrigatedby ditches or acequias. The device which allowed theflowing of water into the ditches across fields, squares,or gardens was a wheel of variable dimension called anoria. More simply, on river banks and along the shorea system of scales and counterweights called shadufwas used.

The plan of irrigated water brought about a kind ofintensive horticulture comparable to that achieved inthe great Asiatic deltas. In the development of thecountryside irrigation allowed plant species whichbecame the basis of the popular diet – e.g., rice andlegumes rich in protein – to become acclimated to theMuslim west. In Andalusia, sugar cane, rice, and cottonwere cultivated.

In plateau regions (Meseta, Morocco, Iran) whereaquifer beds were deep, the most profitable procedurewas the traditional system of qanats. The qanats weredeep drainage tunnels which directed water to springsor artesian wells. Some were over 16 km long, and theirdeep tunnel was dug from the outlet up to the mother-well. The gradient incline of the aquifer bed can rangefrom almost zero to very steep. Well sites were markedand were used for ventilation and disposition of debrisfrom land clearing. The science of the qanats,traditionally, was based on empirical knowledge andwas passed down by gesture or through oral tradition.The earliest descriptions are Iranian. Later they weredeveloped on the Castilian Meseta (Madrid) and inMorocco (in Marrakesh). Today, one can see them inCentral America; they are the oil-qanats.

In between the canals of flowing water and thesystem of qanats the Islamic world watered its gardensand fields, its city courtyards and domestic patios,and its mosques, with water from wells whose volumewas increased through a process described by Ibnal-˓Awwām in the Kitāb al-Filāth. at and in NabateanAgriculture. Chapters relevant to finding the under-ground water level and sinking wells are followedby considerations on ways to increase the volume ofwater stored, ways to raise water from wells that are too

deep, and ways to modify the taste of brackish orsalty water.The detailed observation of the earth or of its

vegetation, in order to identify the presence of water, aswell as the empirical nature of the investigation tosample the earth, in order to define various qualities ofwater, such as neutral, salty, or brackish and bitter,systematically mobilized the senses. Empiricism wasable to bring about the creation of an irrigated,productive agriculture area. This success was builton the very controlled work of the fellahs, a politicalencouragement of individual appropriation, and on ahigh level of applied knowledge.This multisecular, integrated system was the reason

behind the development of numerous plant speciescrucial to the existence of civilization.

See also: ▶Technology in the Islamic World, ▶Agri-culture in the Islamic World, ▶Qanat, ▶Dams inArabia

References

al-Hassan, A. Y. and D. R. Hill, Islamic Technology. Paris:UNESCO, 1986.

Bolens, L. Agronomes andalous du Moyen Age. Genève:Droz, 1981.

---. L’irrigation en Andalusia. El Agua en Zonas Aridas:Arqueologìa e Historia. Almeria: Instituto de EstudiosAlmerienses de la Diputaciòn de Almerìa, 1989. 69–95.

Fahd, T. Un traité des eaux dans al-Filāh. a an-Nabat.iyya. LaPersia nel Medioevo. Roma: Academia dei Lincei, 1971.277–326.

Glick, T. F. ed. Irrigation and Society in Medieval Valencia.Cambridge, Massachusetts: Harvard University Press,1970.

---. Irrigation and Hydraulic Technology in Islamic Spain:Methodological Considerations. Journal of the History ofArabic Science 11 (1997): 3–19.

Watson, A. Agricultural Innovation in the Early IslamicWorld (700–1100). Cambridge: Cambridge UniversityPress, 1983.

Irrigation in South America

GRAY GRAFFAM

Large-scale irrigation systems (canal irrigation) wenthand-in-hand with the rise of cities and truly complexsocieties on the coast of Peru during pre-Hispanictimes. Such systems delivered water to hundreds ofhectares of potentially fertile land along a dry desertcoast. Relatively late in prehistory, from 300 BCEonward, a number of well-known urban cultures (e.g.,Moche, Lima) undertook the construction and expansion

1142 Irrigation in South America

of irrigation works, which supported dense popula-tions. This process culminated around AD 1000 in theconstruction of exceptionally large and sophisticatedworks by the Chimu, including an intervalley canal ofimpressive proportions from the Rio Chicama. Theseworks made it possible for a population of some 25,000to reside at the capital city of Chan Chan. Irrigationagriculture played a primary role in sustaining urbancommunities near the coast, where large irrigable plainsof potentially fertile land were brought into production.

Similar irrigation systems in the Andean highlandsare also of note. Some researchers, such as MichaelMoseley, believe that irrigation agriculture developedhere, as an extension of hunter–gatherer practices.Because of the steep slope, short canals would havebeen sufficient to water desired areas, and over thecourse of a millennium or more, a sophisticated irri-gation technology developed. By AD 600, canalirrigation brought hundreds of hectares of otherwiseunusable land into production in the Ayacucho valleyof south-central Peru. These networks helped supporta population of some 20,000 or more at the urban siteof Huari, which is situated at an elevation of some3,000 m, above any substantial acreage of arable land.

Other agricultural systems are also known for theAndes, and for elsewhere in South America. Theseinclude (a) sunken gardens on the desert coast, whereplots of land were dug down to the water table and thenplanted, (b) terraces along the highland slopes, whichserved to retain moisture and enhance production, and(c) raised or drained fields along lake margins and inthe Amazon basin, which served to reclaim inundatedwetland. Aspects of irrigation technology theoreticallycome into play with each. Upland irrigation tends tocreate a higher water table downslope, which can makesunken fields possible in otherwise very dry areas.Slope irrigation can deliver a supply of water toterraced fields, and such systems are documented forthe Inca. During the dry season, spring water can be runinto the swales of raised field systems, which can allowfor double cropping in some settings, e.g., Lake Titicaca.Irrigation plays a role in other agricultural systems of theAndes. All of these agricultural systems were gearedtoward intensive production, as a means for densehuman adaptation to the Andean environment.

In general, the construction and maintenance ofirrigation systems are portrayed in the archaeologicalliterature as a powerful force leading to the rise ofcivilization and urban life. This theory is based uponthe view expressed by Karl Wittfogel, and subsequent-ly anthropologists such as Julian Steward, that watermanagement plays a key role in crystallizing politicalauthority; it is also referred to as the “HydraulicHypothesis.” According to this theory, highland peoplescame to control a scarce resource of high value –water – which led to a hierarchical system for

its management and distribution. Such a scenario isthought to have led inevitably to the formation ofstratified society and subsequently state bureaucracy.Political power is seen as a direct outgrowth of thestruggle for water, from which centralized authority andstate-level government emerge. Not everyone agrees,and some scholars, such as Robert Adams, have arguedforcefully that irrigation is the consequence of politicalpower, rather than its cause.

The Peruvian data do not support the “HydraulicHypothesis” of civilization’s emergence. A strongmaritime economy typified subsistence strategy alongthe coast during preceramic times, and large aggluti-nated settlements that housed hundreds of people werebuilt along the coast between 2500 and 1800 BCE, e.g.,Huaca Prieta, El Paraiso, Rio Seco, Playa Culebras, andothers. There is an active debate on the role that crops,including maize, had in this developmental process, butit seems quite clear that irrigation agriculture playedlittle part and certainly not to the scale of later times.According to Michael Moseley, the sociopoliticalorganization that accompanied these settlements washighly evolved, incorporating the management of labormobilization (a form of taxation) on a regional basis.Irrigation agriculture took hold around 1800–900 BCEin the prehistoric sequence for Peruvian cultures. Bythis time, authority figures and labor taxation systemshad already emerged. Irrigation technology did notbring them about, but vice versa.

Still, the matter of irrigation’s impact on society is atopic of central concern. For the north coast of Peru, ithas been argued that irrigation technology went hand-in-hand with hierarchical social organization duringlate pre-Hispanic times. According to Patricia Netherly,water was a valuable commodity, and groups benefitedfrom a hierarchically organized social structure, capa-ble of resolving conflict when it occurred. MichaelMoseley adds the perspective that large-scale irrigationprojects were designed and engineered by rulers inthese settings. Together both views provide a clearunderstanding of how irrigation was carried out, onthe one hand through kinship organization, and on theother through government intervention in labor-intensive projects. Irrigation may not have given riseto civilization and urban life in the Andes, but it clearlyevolved within the power structure of subsequentdevelopments.

Today, systems of native irrigation management areunder study, as are the impacts of modern attempts toimprove them (Mitchell 1991; Bolin 1990). It is notedthat highland communities often attempt to maintaintheir rights to water use and management, although inPeru such rights no longer exist in the legal sense. Allwater belongs to the Peruvian state, and there arenational laws and regulations that govern its use.Highlanders, especially those who regard themselves as

Ishango bone 1143

“Owners of the Water,” fall into conflict with peoplein the lowland valleys. According to Bolin, there is agreat need for agricultural and government agencies toinvestigate the indigenous patterns of water use, andthe competition between and within villages for accessto irrigation water. As revealed by Mitchell andNetherly, such patterns of water rights are likely to bedeeply embedded within kinship organization andindigenous social structure.

I

References

Adams, Robert M. The Evolution of Urban Society. Chicago:Aldine, 1966.

Bolin, Inge. Upsetting the Power Balance: Cooperation,Competition, and Conflict Along an Andean IrrigationSystem. Human Organization 49.2 (1990): 140–8.

Hastorf, Christine A. Agriculture and the Onset of PoliticalInequality Before the Inca. Cambridge: Cambridge Uni-versity Press, 1993.

Isbell, William H. and Gordon F. McEwen. Huari Adminis-trative Structure: Prehistoric Monumental Architectureand State Government. Washington, District of Columbia:Dumbarton Oaks Research Library and Collection, 1991.

Mitchell, William P. Peasants on the Edge: Crop, Cult, andCrisis in the Andes. Austin: University of Texas Press,1991.

Moseley, Michael E. The Incas and Their Ancestors: TheArchaeology of Peru. London: Thames and Hudson, 1992.

Netherly, Patricia J. The Management of Late AndeanIrrigation Systems on the North Coast of Peru. AmericanAntiquity 49.2 (1984): 227–54.

Isa Tarjaman

SUN XIAOLI

During the Yuan dynasty (1271–1368) the Arabs playeda role in Chinese science and technology similar to that ofthe Indians in the Tang, bringing in stimulating outsideinfluenceswhichwere then incorporated and synthesizedinto Chinese mathematics, astronomy, and medicine.Isa Tarjaman (1227–1308) or Aixue in Chinese, was aremarkable example. Isa Tarjaman, sometimes calledIsa the Interpreter or Isa the Mongol, was a NestorianArab from Syria. He was skilled as a mathematician andastronomer as well as in medicine and pharmacy. Hecame toChina in about 1247, thenworked for theMongolKhans till his death in 1308. In 1263 Kublai Khanappointed Isa the director of the Muslim Astronomi-cal Bureau and Medical and Pharmaceutical Bureau.During this time he suggested that Kublai prepare a newcalendar in the Arabian style which he finished in 1267in cooperation with a Persian astronomer Zhama Ludin

or Jamāl al-Dīn, who was working in China too. Thiswas called the Wan-nian (ten thousand years) calendar.Meanwhile, they made seven kinds of Arabian astrono-mical instruments for the Huihui (Muslim) Observatory.All of these exerted some influence on the Chineseastronomer Guo Shoujing (1231–1316) and his work.From 1283 to 1286, Isa was sent to Il-khan as a

member of a delegation. There he visited the famousMaraghā Observatory and worked together with someArabian and even Chinese astronomers who wereworking there for a time. Then he brought some of theseastronomical and mathematical works back to China.These were studied by staff members at the MuslimAstronomical Bureau in Beijing.As the director of the Medical and Pharmaceutical

Bureau, Isa Tarjaman established a Capital Hospitalto introduce Arabian medicine to China; his wifeSara also worked there. An important Arabian medicalwork entitled Huihui Yaofang (Collection of MuslimPrescriptions) was compiled under his leadership. It isinteresting that some of the contents of this work weretaken from Ibn Sīnā’s Canon. Therefore, Isa made agreat contribution to the history of the Sino-Arabianscientific exchange, and he thus was praised by theMongol Khans. After returning from Il-Khan he roseto be a Hanlin Academician, then the minister of Statein 1297. After his death the Mongol court made himthe Fuolin Prince. He was the only Arab to attain such ahigh official position in China.

See also: ▶Guo Shoujing, ▶Maraghā

References

Needham, Joseph. Science and Civilisation in China. Vol. 3.Cambridge: Cambridge University Press, 1959.

Shen, Fuwei. Zong Xi Wenhua Jiaoliu Shi (History ofSino-Western Cultural Exchange). Shanghai: People’sPublishing House, 1985.

Song, Lian. Yuan Shi (History of the Yuan Dynasty, 1370).Chap. 134. Biography of Aixue (Isa Tarjaman). Book 11.Beijing: Zhonghua, 1979.

Ishango Bone

ANNE HAUZEUR

The engraved bone drew international attention as soonas it was described by J. de Heinzelin in 1957. Itsuniqueness, as well as its geographical and chronologi-cal position, were astonishing.Ishango is located on the top of a fossil terrace of the

Semliki River, at the mouth of Lake Edward/Rutanzige,

Ishango Bone. Fig. 1 The engraved bone from Ishango,with a quartz at the tip (photo and ©RBINS).

Ishango Bone. Fig. 2 Uurolled sketch of the Ishangobone, and number in each group of notches (after deHeinzelin, 1957).

1144 Ishango bone

in the Democratic Republic of Congo. There wereseveral prehistoric occupations from 20,000 till 5000BC, when the volcano Katwe erupted. The differentlevels of human occupation are characterised either bya great amount of small-sized tools in a translucentwhite quartz, but most of all by numerous boneharpoons. Those latter evolved from a one-barbed sidedto a two-barbed sided type. The settlement of Ishangowould illustrate an old step of this harpoon production,whose pattern would have been widespread from theGreat Lakes region towards Western Africa and theNorth in Sudan and Egypt. Rainfall was increasingduring this time, so that the way of life was moredevoted to fishing. This fishing tradition went on aftersedentarisation and the introduction of animal breeding.

The engraved bone has several points of interest. It isthe only piece among the whole artefacts assemblage tohave a series of notches engraved in a very orderedrhythm (Fig. 1). As with the other tools, it was made onthe settlement. A diaphysis [the mid-section of a longbone] from an unidentified animal was prepared andworked. At one end a little piece of white quartz wasshafted to be used as a tool. Without any archaeologicalevidence the function is unknown; perhaps it was usedto incise or engrave. The “shaft wears” groups ofnotches, displayed in three rows on its periphery. Whenadding all the groups of each row, the sum is 48 or 60,a multiple of 12 (Fig. 2). Each group of notches sums

either prime numbers between 10 and 20, or numbersmultiplied by 2, or 10 � 1. It could illustrate anumerical converter system of base 10/base 12. In sucha case, the Ishango bone could be considered as theoldest computing machine, used during the times ofthe hunter-gatherer nomads. It would be the oldesttranscribed testimony of the mathematical intelligenceof our ancestors, right in Central Africa, some 20,000years ago. Originally, the antiquity of the piece wasquestioned, but new dating has proved its age.

Archaeological facts demonstrate the wide spread ofthe harpoon tradition, i.e., from Central Africa to theNile basin. Traditional scholars teached that the firstmathematics came from the Ptolemaic period and theGolden Age of Alexandria.

See also: ▶Mathematics in Africa

References

Brooks, A. S. and C. Smith. Ishango Revisited: New AgeDeterminations and Cultural Interpretations. The AfricanArchaeological Review 5 (1987): 65–78.

de Heinzelin J. Ishango. Scientific American, 206.6 (1962):105–16.

---. Les Fouilles d’Ishango. Bruxelles: Institut des Parcsnationaux du Congo belge, 1957.

Marshack, A. The Mesolithic Bone: Ishango. The Roots ofCivilization. Ed. Alexander Marshack. New York:McGrew-Hill Book Company, 1972: 27–32.

Ish.āq Ibn H. unayn 1145

Ish. aq Ibn H. unayn

I

GREGG DE YOUNG

Ish.āq ibn H. unayn (215–298 AH/AD 830–910) is bestknown for his role in the translation of Greek texts,both philosophical and mathematical, into Arabic. Inaddition to his work in the translation institute foundedfor his father, H. unayn ibn Ish.āq (193–263 AH/AD809–877), he served as a physician to the court undercaliphs al-Mu a˓tamid and al-Mu a˓tadid. AlthoughH. unayn was a Nestorian Christian, some sources implythat Ish.āq converted to Islam.

As a translator, Ish.āq followed the scientific approachdeveloped and applied by his father with such success tothe Galenic corpus. Rather than translate mechanicallyword-by-word, he attempted to capture the meaning ofeach Greek thought unit in an appropriate form in thetarget language. (Both Ish.āq and his father are said tohave preferred to translate first from Greek into theirnative Syriac, only later producing an Arabic versionbased on the Syriac. Assuming such reports to betrue, the paucity of Syriac translations among extantmanuscripts remains puzzling to historians.)

Ish.āq's greatest contributions lay in his translationsof Greek philosophical texts, especially the works ofAristotle. He produced Syriac versions of a part of thePrior Analytics and all of the Posterior Analytics andthe Topics. He also rendered the Categories, OnInterpretation, Physics, On Generation and Corrup-tion, On the Soul, parts of the Metaphysics, and theNichomachean Ethics into Arabic. He may also havetranslated the Rhetoric and the Poetics. In addition toAristotle's works, he translated Galen's Number of theSyllogism and part of his On Demonstration, as well assome logical and philosophical works by Alexander ofAphrodias, Porphyry, Themistius, and Proclus.

Ish.āq was also instrumental in translating severalimportant Greek mathematical treatises into Arabic.These include Euclid's Elements, Optics, and Data,as well as the Almagest of Claudius Ptolemy, On theSphere and Cylinder by Archimedes, the Sphericsof Menelaus, and minor works by Autolycus and

Hypsicles. It is reported that Ish.āq's translations ofEuclid and Ptolemy were revised by the mathematician,Thābit ibn Qurra. Apparently, Thābit compared theArabic version with additional Greek manuscriptswhich he had at his disposal and noted differencesbetween the Arabic and Greek versions. Whether anyother editing was involved, we do not yet know. Allextant Arabic manuscript copies of Euclid seem toreflect some aspects of this editing process, although nomanuscript contains the complete set of known com-ments attributed to Thābit. The relationship of Ish.āq'sversion of Euclid to the earlier transmission attributedto al-H. ajjāj ibn Yūsuf ibn Mat.ar is difficult to establishbecause the earlier version has disappeared. In thecase of the Almagest, however, both Arabic versionsappear to be extant, allowing some conjectures to bemade concerning the translation principles applied byboth men.Ish.āq also produced a number of original works on

medicine. Unfortunately, these seem not to havesurvived. His Tārīkh al-At.t.ibā˒ (History of Physicians),an extended version of a Greek book of the same titleby John Philoponus, does survive. Ish.āq has added thenames of philosophers active during the lifetime ofeach physician mentioned. This work has been helpfulto historians of both medicine and philosophy.

See also:▶H. unayn ibn Ish.āq,▶Almagest,▶Thābit ibnQurra, al-H. ajjāj

References

De Young, G. The Arabic Textual Traditions of Euclid'sElements. Historia Mathematica 11 (1984): 147–60.

De Young, G. Ish.āq ibn H. unayn, H. unayn ibn Ish.āq, and theThird Arabic Translation of Euclid's Elements. HistoriaMathematica 19 (1992): 188–99.

Kunitzsch, P. Der Almagest: Die Syntaxis Mathematica desClaudius Ptolemaius in arabisch-lateinischer Überliefer-ung. Weisbaden: Harrassowitz, 1974.

Kunitzsch, P. Findings in Some Texts of Euclid's Elements(Medieval Tranmission, Arabo-Latin). Mathemata: Fest-schrift für Helmuth Gericke. Ed. M. Folkerts andU. Lindgren. Wiesbaden: Franz Steiner, 1985. 115–28.

Shehaby, N. Ish.āq ibn H. unayn, Abū Ya q˓ūb. Dictionary ofScientific Biography.Vol. 7. Ed. C. C. Gillispie. New York:Scribner, 1970–1981. 24–6.