He lived in Damascus at least until the year 1258, where he is believed to have written the Tāj; 20 years in Maragha; Works: Tāj al-Azyāj (The Crown of Astronomical Handbooks), or at least the first version of it; Taḥrīr al-Uṣūl (Recension of Euclid’s Elements) in Maragha; 1275 composed his second zīj, Adwār al-anwār  madā al-duhūr wa-’l-akwār, introducing the results of the astronomical observations he carried out in Marāgha.  [BEA, Comes]