Nasir al-Din al-Tusi
Iranian astronomer, mathematician, philosopher, and Shia theologian (1201–1274), founder of the Maragheh observatory, who devised the 'Tusi couple' in astronomy.
Read in context →At a glance
- Field
- Astronomy, mathematics, philosophy, theology
- Era
- Mongol / Ilkhanid era
- Key work
- Maragheh observatory; Zij-i Ilkhani; the Tusi couple
- Birthplace
- Tus, Khorasan
Biography
Khwaja Nasir al-Din Muhammad ibn Muhammad al-Tusi (1201–1274 CE), an Iranian scholar from Tus in Khorasan, was one of the greatest astronomers, mathematicians, and philosophers of the medieval world. He spent part of his life under the protection of the Nizari Ismailis in the fortresses of Alamut, where he wrote important works including the ethical treatise Akhlaq-i Nasiri. After Hulagu Khan's Mongols took Alamut and Baghdad, Tusi entered Ilkhanid service and persuaded them to found the great Maragheh observatory — a scientific institution with precise instruments, a vast library, and a team of scholars whose collaborative work produced the Ilkhanic Tables (Zij-i Ilkhani). In astronomy he devised the innovative geometric device known as the 'Tusi couple,' which generates linear motion from two circular motions and is thought to have later influenced Copernicus; in mathematics he established trigonometry, especially spherical trigonometry, as an independent discipline. A contested point is his role in the fall of Baghdad and the end of the Abbasid Caliphate in 1258: some sources — especially later Sunni writers — portray him as an influential adviser who encouraged Hulagu, but many modern scholars regard this account as exaggerated or partisan, rooted in sectarian hostility.
Related entities
Sources
- Encyclopaedia Iranica, "Naṣīr-al-Dīn Ṭūsī"
- Encyclopaedia Britannica, "Nasir al-Din al-Tusi"
- George Saliba, Islamic Science and the Making of the European Renaissance (2007)