Banū Mūsā were three Arab brothers who made great contributions to science in the A.D. 800’s. Their names were Muhammad, Ahmad, and Hasan. The brothers did important work in the fields of astronomy, mathematics, and mechanics.
Muhammad, Ahmad, and Hasan lived from the early 800’s to the mid-800’s in Baghdad, in what is now Iraq. Banū Mūsā means sons of Musa in Arabic. They were the sons of Mūsā ibn Shākir, a bandit who became a renowned astronomer. Ibn Shākir was a close companion of al-Ma’mūn, who later became a caliph (ruler) of the Islamic empire. After their father’s death, al-Ma’mūn acted as guardian to the brothers, who received a fine education under his care.
The Banū Mūsā hired such famous translators as Hunayn ibn Ishāq and Thābit ibn Qurra to translate many ancient Greek works into Arabic. These works included medical treatises and geometry texts. They compiled The Book of Ingenious Devices from translated descriptions of mechanical devices from ancient Greece and Rome, along with their own improvements and inventions. Many of the devices described in the book are trick vessels that hold or distribute liquids in unexpected ways.
The brothers designed bridges and canals for the caliphate. They were also involved in al-Ma’mun’s expedition to the Plain of Sinjar, in what is now northern Iraq, where they performed measurements to confirm the circumference of Earth calculated by other scholars. The brothers also calculated the length of the solar year to be 365 days and 6 hours.
The three brothers were known for their competitive and arrogant nature. They sabotaged rivals to put them out of favor with the caliphs. The brothers’ chief rival was the philosopher al-Kindī. According to one account, they persuaded the caliph al-Mutawakkil to have al-Kindī beaten and then confiscated his library for their own use.
Arabic and international scholars studied the Banū Mūsā’s works in mathematics and mechanics for many generations. The brothers’ extensive work in geometry was especially influential. Among other innovations, they introduced new ways to calculate the area and volume of a variety of large or complex shapes and forms.
