Abº al-Qæsim AÒbagh ibn MuÌammad ibn al-SamÌ died in Grenada on ‘Tuesday, on the twelfth remaining night of Rajab, in the year four hundred and twenty-six, at the age of fifty-six solar years’;1 i.e. Tuesday, 27th May 1035,2 implying that he was born in 979. While it appears that he was born in Cordoba, he came to Grenada to work with the Emir Îabbºs ibn Mæksan (1019-1038 ca). We also know that he was a follower of the famous astronomer and mathematician Maslama al-Majrî†î, who died in 398/1007-1008. A contemporary of mathematicians such as Ibn alHaytham, Ibn al-SamÌ produced a substantial and important body of work in his own right in the fields of mathematics and astronomy. From the titles of his works as listed by ∑æ‘id,3 it is clear that his interests included number theory, geometry, the geometry of the astrolabe, etc. His works encompass

also a commentary on Euclid’s Elements, and ‘a great book on geometry with an exhaustive discussion of the parts concerning the line: straight, arched and curved’.4