Kharidjites

The Kharidjites, meaning "those who went out," were an early Islamic sect that emerged during the First Fitna, the first Muslim civil war. Their origins trace back to a dispute over the caliphate following the assassination of the third caliph, Uthman. A significant number of Ali ibn Abi Talib's supporters were displeased when he agreed to arbitration with his rival Mu'awiyah. This group broke away from Ali, leading to their designation as Kharidjites.

Their core theological tenet was that any pious Muslim, regardless of lineage or tribal affiliation, could be caliph. They rejected the legitimacy of both Uthman and Mu'awiyah, and initially Ali, due to their perceived deviations from Islamic principles. Kharidjites were known for their austere lifestyle, extreme piety, and strict interpretation of the Quran.

This strictness often manifested in a belief that Muslims who committed grave sins were apostates and outside the faith, and therefore could be legitimately killed. This view led to violent confrontations and persecution by the established caliphates. Over time, the movement fragmented into various sub-sects, and their influence waned significantly by the Umayyad and Abbasid periods, though some groups persisted for centuries. Their legacy is primarily one of radical dissent and a challenge to the evolving political and theological landscape of early Islam.