fl. 786-d. 833
Arab scholar who was first to translate Euclid's Elements, and one of the first to translate the Almagest of Ptolemy, from Greek into Arabic. Al-Hajjaj actually translated the Elements twice, first for the caliph Harun al-Rashid (766-809), and later for another caliph, al-Ma'mun (786-833). As for the Almagest, the European name for this work comes from al-Hajjaj's translation of the title, Kitab al-mijisti.