Banū Mūsā

Banū Mūsā
An illustration of a self-trimming lamp from Ahmad's On Mechanical Devices, written in Arabic.
Born	9th century
Residence	Baghdad
Academic background
Influences	Apollonius of Perga, Ptolemy, Galen, Al-Maʾmūn, Mūsā ibn Shākir, Yahya ibn Abi Mansur
Academic work
Era	Islamic Golden Age
Main interests	Astronomy, geometry
Notable works	Book of Ingenious Devices, Book on the Measurement of Plane and Spherical Figures
Notable ideas	Application of arithmetic to geometry
Influenced	Thabit ibn Qurra, Hunayn Ibn Ishaq, Ibn al‐Haytham, Naṣīr al‐Dīn al‐Ṭūsī, Gerard of Cremona, Leonardo Fibonacci, Jordanus de Nemore, Roger Bacon

The Banū Mūsā brothers ("Sons of Moses"), namely Abū Jaʿfar, Muḥammad ibn Mūsā ibn Shākir (before 803 – February 873), Abū al‐Qāsim, Aḥmad ibn Mūsā ibn Shākir (d. 9th century) and Al-Ḥasan ibn Mūsā ibn Shākir (d. 9th century), were three 9th-century scholars who lived and worked in Baghdad. Of Persian descent, they are known for their Book of Ingenious Devices on automata (automatic machines) and mechanical devices. Another important work of theirs is the Book on the Measurement of Plane and Spherical Figures, a foundational work on geometry that was frequently quoted by both Islamic and European mathematicians.

The Banu Musa worked in astronomical observatories established in Baghdad by the Abbasid Caliph al-Ma'mun as well as doing research in the House of Wisdom. They also participated in a 9th-century expedition to make geodesic measurements to determine the length of a degree.

The Banu Musa were the three sons of Mūsā ibn Shākir, who earlier in life had been a highwayman and astronomer in Khorasan of unknown pedigree. After befriending al-Ma'mun, who was then a governor of Khorasan and staying in Marw, Musa was employed as an astrologer and astronomer. After his death, his young sons were looked after by the court of al-Maʾmūn. Al-Maʾmūn recognized the abilities of the three brothers and enrolled them in the famous House of Wisdom, a library and a translation center in Baghdad.

Studying in the House of Wisdom under Yahya ibn Abi Mansur, they participated in the efforts to translate ancient Greek works into Arabic by sending for Greek texts from the Byzantines, paying large sums for their translation, and learning Greek themselves. On such trips, Muhammad met and recruited the famous mathematician and translator Thābit ibn Qurra. At some point Hunayn ibn Ishaq was also part of their team. The brothers sponsored many scientists and translators, who were paid about 500 dīnārs a month. If it wasn't for the brothers' efforts, many of the Greek texts that they translated would have been lost and forgotten.