The Kharijite position on grave sin grew directly out of the Battle of Siffin in 657, fought between Ali, the fourth caliph, and Muawiya, the governor of Syria who contested his succession. When Ali agreed to settle the dispute by arbitration rather than continued fighting, a faction within his own army rejected the agreement outright, holding that judgment belonged to God alone and that Ali had sinned gravely by submitting a matter of right rule to human arbitrators. From that founding grievance the group, who took the name Kharijites, those who go out, from their withdrawal from Ali's camp, drew a wider theological conclusion: that grave sin of any kind puts the person who commits it outside the community of belief entirely, stripping a wrongdoer, ruler or otherwise, of any claim to be a believer at all. The Venture of Islam traces how this reasoning made the Kharijite position inseparable from a political one, since a ruler who governed unjustly had, on this account, ceased to be Muslim and so could rightly be resisted and even killed, a conclusion later Kharijite factions carried into repeated armed uprisings against Umayyad governors and, at the doctrine's origin, against Ali himself, whom a Kharijite assassin killed in 661 for having accepted the arbitration the group had condemned.