Nasir al-Din al-Tusi

Muhammad ibn Muhammad ibn al-Hasan al-Tusi, known as Nasir al-Din al-Tusi (597–672 AH / 1201–1274 CE), was a Persian polymath who made significant contributions to mathematics, astronomy, philosophy, and Islamic theology. He served the Ismaili order in Alamut before being captured by Hulagu Khan (the Mongol ruler), whom he then served. He founded the Maragha Observatory in Azerbaijan, which became the most advanced astronomical observatory of its time. His Zij-i Ilkhani remained the standard astronomical reference for centuries. He also wrote on ethics (Akhlaq-i Nasiri) and theology. His work preserved and transmitted much of the Islamic scientific tradition after the Mongol invasion. Note: His association with Ismailis and later Mongols was controversial; his scientific contributions are significant.