MĀSHĀʾALLAH (Heb. Manasseh) B. ATHAŇ (754–813), astronomer. Mashāʾallah was probably born in Egypt, which is possibly the reason why he was also called al-Miṣrī, the Egyptian, but part of his life was spent at the court of the caliphs al-Manṣūr and al-Maʾmūn in Damascus. His name appears in many different versions, such as Macha Allah al Mesri, Mashallah, Messahalla, Messahalac, Messalahach, Masalla, Mescallath, Macelama, Macelarama – mainly due to distortions in Latin manuscripts.
Mashāʾallah was one of the earliest independent and original scientific thinkers and scholars. His main efforts led to the transfer of astronomical knowledge from the East to the West by means of later translation; he also adapted Arabic data for the Cordoba astronomical tables. Unfortunately, none of his writings appears to have survived in the original texts and the main source is Latin translations, some of which give rise to confusion, since they list the same works under different titles. Mashāʾallah may also have written an interesting astrological treatise in Hebrew She'elot, which was translated about 1146–48 by Abraham *Ibn Ezra. In 1493 and again 1519 there appeared in Venice a smaller treatise on lunar and solar eclipses, Epistola de rebus eclipsium et de conjunctionibus planetarum in revolutionibus annorum mundi… translated by Johannes Hispalensis from a Hebrew text. Some of the available manuscripts list 12 short chapters, all beginning with the words "Mashāʾallah says…" His treatise on the astrolabe was translated into Latin and English (R.T. Gunther, Chavuv and Messahalla on the Astrolabe (1929). A crater on the moon is named after him.
Steinschneider, Arab Lit, 15–23; Steinschneider, Uebersetzungen, nos. 378–9; G. Sarton, Introduction to the History of Science, 1 (1927), 531; Brockelmann, Arab Lit, supplement, 1 (1937), 391; F.J. Carmoly, Arabic Astronomical and Astrological Sciences in Latin Translation (1956), 23–38.