From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 578

Courtesy of

Isāq ibn unayn: Abū Yaʿqūb Isāq ibn unayn ibn Isāq al‐ʿIbādī

Glen M. Cooper

Borncirca 830

DiedBaghdad, (Iraq), 910/911

Isāq ibn unayn was one of the most important translators of Greek scientific and mathematical works into Arabic. He lived in the ʿAbbāsid capital of Baghdad during the vibrant period of the Graeco–Arabic translation movement, when nearly everything of philosophical or scientific interest from the ancient Greek corpus was translated into Arabic.

Isāq came from a family noted for its translations. He was the son of the most renowned translator of the period, unayn ibn Isāq, who hailed from a Nestorian Christian Arab tribe of al‐īra, Iraq. unayn set the standard of excellence, professionalism, and method for Graeco–Arabic translation, which he passed on to his son. Like his father, Isāq was a physician and wrote an important history of physicians that supplements our information on that subject derived from classical sources. unayn reports in the epistle in which he describes the 129 works of Galen he translated or revised that he translated several books of Galen specifically for the use of his son Isāq, perhaps for him to study as part of his education as a physician.

Although Isāq was a physician, he understood mathematics and astronomy in order to be able to grasp the sophisticated arguments of Euclid's Elements and Ptolemy's Almagest, both of which he translated from Greek into Arabic. These two works, which were of immense importance for the subsequent development of Greek mathematical astronomy into the Islamic world, were Isāq's primary contribution to astronomy. The Elements were useful not only for instruction in geometry but also as a model for presenting scientific theory systematically and deductively; it was considered by many ancient scholars the foremost example of the methods expounded by Aristotle in his Posterior Analytics. The Almagest was a comprehensive approach to mathematical astronomy from which a long tradition of practice, criticism, and improvement evolved in the Islamic world. Isāq's translation of the Almagest was emended by the practicing astronomer, Thābit ibn Qurra, who perhaps refined the mathematical details. Though the Elements and the Almagest were translated multiple times in the 9th century, which is an indication of the ʿAbbāsid interest in the ancient Greek scientific heritage and the substantial financial support provided for translation into Arabic, it is important to note that the Isāq/Thābit translation became standard for both the Elements and the Almagest.

Isāq translated a number of other works from Greek. These included Euclid's Optics; the Spherics of Menelaus; On the Moving Sphere by Autolycus; several Platonic dialogues; and works of Aristotle, including On the Soul and the Physics.

Selected References

Brentjes, Sonja (1996). “The Relevance of Non‐primary Sources for the Recovery of the Primary Transmission of Euclid's Elements into Arabic.” In Tradition, Transmission, Transformation: Proceedings of Two Conferences on Pre‐modern Science Held at the University of Oklahoma, edited by F. Jamil Ragep and Sally P. Ragep, with Steven Livesey, pp. 201–225. Leiden: E. J. Brill.

Frank, Richard M. (1958–1959). “Some Fragments of Ishāq's Translation of the De Anima.” Cahiers de Byrsa 8: 231–252.

Gutas, Dimitri (1998). Greek Thought, Arabic Culture: The Graeco–Arabic Translation Movement in Baghdad and Early ʿAbbāsid Society (2nd4th/8th10th centuries). London: Routledge.

Ibn al‐Nadīm (1970). The Fihrist of al‐Nadīm: A Tenth‐Century Survey of Muslim Culture, edited and translated by Bayard Dodge. 2 Vols. New York: Columbia University Press.

Kunitzsch, Paul (1974). Der Almagest: Die Syntaxis Mathematica des Claudius Ptolemäus in arabisch–lateinischer Überlieferung. Wiesbaden: Otto Harrassowitz.

Rashed, Roshdi (1989). “Problems of the Transmission of Greek Scientific Thought into Arabic: Examples from Mathematics and Optics.” History of Science 27: 199–209.

Rosenthal, Franz (1954). “Ishāq b. Ḥunayn's Taʾrīf al‐Aibbāʾ.” Oriens 7: 55–80.