Abu Jaffar Muhammad b. Muhammad b. al-Ijlasan Nasir al-Din-Tusi was born on Saturday (at dawn according to Ridawil), 11 Jumada I, 597 H./17 February 1201 A.D. in Tiis or its environsz and died in Baghdad (at sunset according to Bahrani3), 18 Dhii Hl~HIjjH 672 H./25 June 1274 A.D. In a remarkable century that began with the death of Chu Hsi and further witnessed the birth, death or both of such luminaries as Roger Bacon, Ibn °Arabi, Maimonides, Gregory Chioniades, Ibn Taymiyya, Thomas Aquinas and Levi ben Gerson, Tfisi’s breadth and depth of learning stand out.
Nasiruddin al tusi studied the works of his famous persian predecessor with Farid-al-din. Even in his lifetime he was something of a legend and acquired the honorific title of khatija (distinguished scholar and teacher); later he came to be referred to by the rather more impressive ustedh al-bashar (teacher of mankind) and al-mucallim al-thdlith (the third teacher, 1'. e. Rafter Aristotle and Farabi).