Abū Maʿshar Jaʿfar b. Muḥammad b. ʿUmar al-Balkhī, known in the West as Albumasar (d. 272/886), is the best-known astrologer of classical Islam. Many of his works were translated into Latin and had a lasting influence on European science and philosophy. He was born in Balkh on 21 Ṣafar 171/10 August 787 (if one accepts the horoscope in his work Revolutions of the years of nativities , vol. 3, chap. 1, as his own) and died, according to the Fihrist of Ibn al-Nadīm (which gives the