ABSTRACT
Introduction In a previous article, published in 1979, I have described in some detail the planetary model of Mu'ayyad al-Dm al-'Ur<JI of Damascus (d. A.D.1266).1 In that article I published a working edition of the relatively short Arabic text describing the model, and appended to it an English translation and a commentary. The purpose of that article was to show that the planetary model, hitherto ascribed to Qutb al-Dm al-Shirazi (d. A.D. 1311), was in fact due to the Damascene astronomer Mu'ayyad al-Dm al-'Ur<Ji.
