Companion of the Prophet Muhammad, third caliph in the succession of early leaders. From the powerful Umayyad clan. Despite his family's opposition to Muhammad, Uthman was among the first converts and married two daughters of Muhammad, first Rukayya and then Umm Kalthum. Uthman was elected caliph by a committee appointed by his predecessor, Umar, on his deathbed. Under his leadership, the text of the Quran was standardized, with variant collections being destroyed. He appointed many relatives to high positions. Popular discontent led to a mutiny of troops, who killed him in 656. The nomination of Ali as his successor led to the first major civil war in Islam.