Muhammad ibn Musa Al-Khwarizmi (780 - 850) was the most influential mathematician of the Arab Golden Age. His most important book 'Hisab al-jabr w'al-muqabala' has given us the word algebra. Unlike the popular perception, he rejected algebraic symbolism (his treatment was entirely rhetorical) and much of his work was based on earlier Indian and Greek sources which questions his position as the father of algebra. The word 'Algorithm' is a derived from his name. (Source: Hollingdale, Stuart, (1989), Makers of Mathematics)