As a young man he participated in the founding of Baghdad in 762 by working with a group of astrologers led by Naubakht the Persian to pick an electional chart for the founding of the city. He wrote over twenty works on astrology, which became authoritative to astrologers in later centuries at first in the Middle East, and then in the West when horoscopic astrology was transmitted back to to Europe beginning in the 12th century.
His real name was either Manasseh or Jethro, and Latin translators named him Messahalla (with many variants, such as Messahala, Messala, Macellama, Macelarma). He flourished under the Caliph al-Mansur, and became one of the earliest astrologers and astronomers of the Islamic era.
Of his 20+ works, few remain. Only one of his writings is still extant in it's original Arabic, but there are many medieval Latin and Hebrew translations. One of His most popular books in the Middle Ages was the De scientia motus orbis, translated by Gherardo Cremonese.
He also wrote treatises on Astrolabes. (p 10) The De scientia motus orbis is probably the treatise called in Arabic "the twenty-seventh;" printed in Nuremberg 1501, 1549. The second edition is entitled: 'De elementis et orbibus coelestibus', and contains 27 chapters. The De compositione et utilitate astrolabii was included in Gregor Reisch: Margarita phylosophica (ed. pr., Freiburg, 1503; Suter says the text is included in the Basel edition of 1583). Other astronomical and astrological writings are quoted by Suter and Steinsehneider.
An Irish astronomical tract also exists based in part on a mediaeval Latin version. Edited with preface, translation, and glossary, by Afaula Power (Irish Texts Society, vol. 14, 194 p., 1914.}
He died in 815 AD.