Abu Bakr (or Abu-Bekr) (573–634)

Muslim caliph (civic and religious leader of Islam) from 632 to 34. Born Abd-al-Ka'aba, he adopted the name Abu Bakr (‘Father of the virgin’) about 618 when the prophet Muhammad married his daughter Ayesha. He was a close adviser to Muhammad in 622–32 and succeeded the prophet as political leader at his death. As the first Muslim caliph he imposed Muslim authority over all the Arab tribes, added Mesopotamia to the Muslim world, and instigated expansion of Islam into Iraq and Syria.