Muhammad ibn Muhammad ibn al-Hasan al-Tūsī;
(Persian: محمد بن محمد بن حسن طوسی 18 February 1201 – 26 June 1274), better known as Nasir al-Din Tusi (Persian: نصیر الدین طوسی; or simply Tusi /ˈtuːsi/ in the West), was a Persian polymath, architect, philosopher, physician, scientist, and theologian. He is often considered the creator of trigonometry as a mathematical discipline in its own right. He was a Twelver Muslim. The Muslim scholar Ibn Khaldun (1332–1406) considered Tusi to be the greatest of the later Persian scholars.