Al-Majriti

Abu al-Qasim Maslama ibn Ahmad al-Majriti was one of the leading scientists of Muslim Spain (al-Andalus). His epithet "al-Majriti" means "of Majrit," the small frontier town that later grew into Madrid, where he is reported to have been born around 950 CE; the birth date is a modern estimate and not firmly attested. As a young man he traveled to Cordoba, the Umayyad caliphal capital, where he studied, taught, and worked until his death in 398 AH (1007 CE).

He is best remembered as an astronomer and mathematician. His major attested achievement was reworking the astronomical tables (zij, a handbook of tables for computing planetary positions) of the ninth-century scholar al-Khwarizmi: he adapted them to the meridian (the reference line of longitude) of Cordoba and recalculated dates from the Persian to the Islamic Hijri calendar. He also commented on Ptolemy's Planisphaerium, a Greek treatise on mapping the sphere, and worked on commercial arithmetic. Tradition credits him with founding a school of scholars in Cordoba; documented students such as Ibn al-Samh and Ibn al-Saffar carried the exact sciences across the peninsula.

Later writers, including the historian Ibn Khaldun, attributed two works on magic and alchemy — the Rutbat al-Hakim and the Ghayat al-Hakim (known in Latin as the Picatrix) — to al-Majriti. Modern scholars regard this as a misattribution, often citing a different, earlier Maslama; the historian Maribel Fierro has proposed Maslama al-Qurtubi as the likelier author.