Redirected from Sunni
In Islam political disagreements have usually manifested themselves as religious disagreements; the earliest example of this is that 30 years after Muhammed's death, the Islamic community plunged into a civil war that gave rise to three sects. One proximal cause of this first civil war was that the Muslims of Iraq and Egypt resented the power of the third Caliph and his governors; another cause was business rivalries between factions of the mercantile aristocracy. After the Caliph was murdered, war broke out in full force between different groups, each fighting for power. The war ended with a new dynasty of Caliphs who rules from Damascus.
One of the groups to evolve from this conflict was the Sunnis. They hold themselves as the followers of the sunna (practice) of the community a whole. They were willing to recognize the authority of the Caliphs, who maintained rule by law and persuasion, and by force if necessary. The sunnis became the largest division of Islam.
Two smaller groups also were created from this schism: The Shi'ites and the Kharijites (Khawarij), also known as the seceders. The Shi'ites believed that the only legitimate leadership rested in the lineage of Muhammed's cousin and son-in-law, 'Ali. The Shi'ites believed that the rest of the Muslim community committed a grave error by electing Abu Bakr and his two successors as leaders.
A third group came into being which rejected the Sunni and Shi'ite positions; they maintained that the community had the right to elect its own head, and even should have the power to depose of bad leaders. This group held that leadership should be based on Islamic scholarship and the will of the people, and not on inherited power. This group was labeled by other Muslims as Kharijites[?], or the Khawarij (seceders).
Beliefs of the Ahl us Sunnah (http://www.geocities.com/haadi_islam/beliefs/aqeedah.htm)