born AD 586, Mecca, Arabian Peninsula died Nov. 3, 644, Medina Second Muslim caliph (634-644). He initially opposed the Prophet Muhammad but became a Muslim 615. His daughter afah married Muhammad in 625. He was nominated by Ab Bakr as his successor. As caliph he spread Islam to Egypt, Syria, and Persia. His innovations affected taxation, social welfare, and the empire's entire financial and administrative fabric, and he was noted for his justice, social ideals, and candour