Seven Chapters of Ibn Al-Saffar's lost ZĪj *

Abū-1-Qásim Ahmad b. ʿAbd Allah b. ʿUmar (d. 1035), known as Ibn al-Saffar, was one of the disciples of Maslama al-Majritl (d. 1008) traditionally associated with the Cordovan revision of al-Khwarizml’s ztj. Saʿid al-AndalusI states that he wrote a Ztj mukhtasar ʿald madhhab al-Sindhind (“an abridged ztj according to the Sindhind school”) ¹ . This is probably the work quoted by Abraham b. ʿEzra in the 12^th c. ² : this latter author states that Ibn al-Saffar was responsible for the change from the Persian calendar and the Yazdijird era used by al-Khwarizml to the Muslim calendar and the Hijra era which appears in the Latin version of Adelard of Bath, but Saʿid attributed this change to Maslama al-Majritl ³ . According to IbnʿEzra, Ibn al-Saffar corrected the position of the apogee of Saturn from 8^s 20;55° to 8^s 4;55°, which he considered to be the correct longitude in al-Khwarizml’s ztj, stating that the translator(?)/copyist (ipsum qui transtulit) had been mistaken by the similarity of the form of the 20 (kdf) and the 4 (ddl) ⁴ . It is clear now that this correction in Saturn’s apogee was an error made by Ibn al-Saffár ⁵ which appears in Adelard of Bath’s Latin translation ⁶ . We will try to show in this paper that there might be, at least, one other instance in which Ibn al-Saffár’s and Maslama’s materials have been mixed in Adelard’s translation.