Maslamah ibn Aḥmad Majrīṭī

Abu al-Qasim Maslama ibn Ahmad al-Majriti (: c. 950–1007), known in European Latin-language sources as , was a Muslim Arab astronomer, alchemist, mathematician, economist and scholar in al-Andalus, active during the reign of Al-Hakam II. His full name is Abu 'l-Qāsim Maslama ibn Aḥmad al-Faraḍī al-Ḥāsib al-Maj̲rīṭī al-Qurṭubī al-Andalusī.

Achievements Al-Majrīṭī took part in the translation of Ptolemy's Planisphaerium, improved existing translations of the Almagest, introduced and improved the astronomical tables of Muhammad ibn Musa al-Khwarizmi, aided historians by working out tables to convert Persian dates to Hijri years, and introduced the techniques of surveying and triangulation.

Al-Majrīṭī was one of the earliest alchemists to record the usage and experimentation of mercury(II) oxide.

According to Said al-Andalusi, he was the best mathematician and astronomer of his time in al-Andalus.

Al-Majrīṭī also predicted a futuristic process of scientific interchange and the advent of networks for scientific communication. He built a school of Astronomy and Mathematics and marked the beginning of organized scientific research in al-Andalus. Among his students were Ibn al-Saffar, Abu al-Salt, and at-Turtushi.

The two works are the "Sage's Step/The Rank of the Wise" (Rutbat al-hakim?1009) and the Picatrix. Both were translated into Latin, in a version somewhat bowdlerised by Christian dogma, in 1252 on the orders of King Alfonso X of Castile; the original Arabic text dates probably from the middle of the eleventh century.

The Rutbat includes alchemical formulae and instructions for purification of precious metals, and was also the first to note the principle of conservation of mass, which he did in the course of his pathbreaking experiment on mercury(II) oxide:

The Picatrix is more concerned with advanced esotericism, principally astrology and talismanic magic, although he also goes into prophecy. The author considers this the advanced level of work, occasionally referring to the Rutbat as the foundation text.

Supposed daughter

Several modern sources state that al-Majriti had a daughter, Fátima de Madrid, who was also an astronomer. However, the earliest known mention of her is a short biographical article on her in the Enciclopedia universal ilustrada europeo-americana, published in the 1920s.