From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 942

Courtesy of

īzāde al‐Rūmī: alā al‐Dīn Mūsā ibn Muammad ibn Mamūd al‐Rūmī

F. Jamil Ragep

BornBursa (Turkey), circa 1359

DiedSamarqand (Uzbekistan), after 1440

īzāde al‐Rūmī was known for his works in mathematics and astronomy, which were used extensively as teaching texts. He left his native Bursa, where his grandfather had been a prominent judge and his father an eminent scholar, and traveled to Persia in order to gain a higher level of proficiency in the philosophical and mathematical sciences. His nickname indicates his family's standing (Qāīzāde = son of the judge) and his origins (Rūmī = from what had been part of the eastern Roman Empire). He studied with many learned scholars in Khurāsān and Transoxiana, among whom was the famous theologian al‐Sayyid al‐Sharīf al‐Jurjānī at the court of Tīmūr in Samarqand. Qāīzāde, however, felt that Jurjānī was deficient in the mathematical sciences. After Tīmūr's death, Qāīzāde found both a student and a patron in Tīmūr's grandson Ulugh Beg, also in Samarqand.

īzāde joined a group of scholars in the circle of Ulugh Beg that taught mathematics and astronomy, as well as other sciences. He became the head of the madrasa (school) of Samarqand, and Ulugh Beg often attended his lectures. Qāīzāde also became one of the directors of the Samarqand Observatory after the death of Jamshīd al‐Kāshī in 1429, and he undertook its observational programs assisted by ʿAlī al‐Qūshjī, who continued the program after Qāīzāde's death.

īzāde was not known for his innovations or creativity. He was most famous for his commentaries on Mamūd al‐Jaghmīnī's astronomical compendium entitled al‐Mulakhkhaʿilm al‐hayʾa al‐basīa (1412) and Shams al‐Dīn al‐Samarqandī's geometrical tract Ashkāl al‐taʾsīs (completed: 1412); the large number of extant manuscripts of both commentaries indicates their enduring popularity as teaching texts. Therefore, it is not surprising that one also finds supercommentaries on Qāīzāde's commentaries written by many scholar–teachers including Sinān Pāshā (died: 1486), ʿAbd al‐ʿAlī al‐Bīrjandī (died: 1525/1526), Bahāʾ al‐Dīn al‐ʿĀmilī (died: 1621), and Qāīzāde's student Fatallāh al‐Shirwānī (died: 1486). All of these individuals continued the tradition established at Samarqand, thereby disseminating the mathematical sciences throughout Ottoman and Persian lands. Also noteworthy is that the marriage of Qāīzāde's son to Qūshjī's daughter would eventually sire the famous Ottoman astronomer–mathematician Mīram Čelebī (died: 1525).

A number of other astronomical works are sometimes attributed to Qāīzāde, including a supercommentary on ūsī's commentary (tarīr) of the Almagest and a treatise on the sine quadrant, but it is not clear which of these are authentic. The ascription of a commentary (Shar) on Naṣīr al-Dīn al-Ṭūsī's major astronomical work al‐Tadhkira fī ʿilm al‐hayʾa (Biblioteca Medicea Laurenziana or. MS 271) to Qāīzāde is certainly not correct; this manuscript is actually an incomplete copy of the commentary by Jurjānī.

Among Qāīzāde's mathematical works is a treatise on determining the value of sin 1°, for which he seems to have relied heavily on the work of Kāshī. Qāīzāde's only philosophical or theological work is a supercommentary on Athīr al‐Dīn al‐Abharī's Hidāyat al‐ikma, although he intended to write a refutation of parts of Jurjānī's famous commentary on the Persian ʿAud al‐Dīn al‐Ījī's (circa: 1281–1355) Mawāqif.

Selected References

Bagheri, Mohammad (1997). “A Newly Found Letter of Al‐Kāshī on Scientific Life in Samarkand.” Historia Mathematica 24: 241–256.

Brockelmann, Carl. Geschichte der arabischen Litteratur. 2nd ed. Vol. 1 (1943): 616–617, 624, 674–675; Vol. 2 (1949): 275, 276; Suppl. 1 (1937): 850, 865. Leiden: E. J. Brill.

Fazlıoğlu, İhsan (2003). “Osmanlı felsefe‐biliminin arkaplanı: Semerkand matematik‐astronomi okulu.” Dîvân İlmî Araştırmalar1: 1–66.

Kennedy, E. S. (1960). “A Letter of Jamshīd al‐Kāshī to His Father: Scientific Research and Personalities at a Fifteenth Century Court.” Orientalia 29: 191–213. (Reprinted in E. S. Kennedy, et al. (1983). Studies in the Islamic Exact Sciences, edited by David A. King and Mary Helen Kennedy, pp. 722–744. Beirut: American University of Beirut.)

Rosenfeld, B. A. and Ekmeleddin Ihsanoğlu (2003). Mathematicians, Astronomers, and Other Scholars of Islamic Civilization and Their Works (7th–19th c.). Istanbul: IRCICA, pp. 272–274.

Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society.

Tashköprüzāde (1985). Al‐Shaqāiʾq al‐nuʿmāniyya fī ʿulamāʾ al‐dawlat al‐ʿuthmāniyya, edited by Ahmed Subhi Furat. Istanbul: Istanbul University. pp. 14–17.