the Sunni-Shia divide. Shia Muslims refused to accept the legitimacy of the Umayyad caliphate, or indeed the legitimacy of Abu Bakr, Umar, and Uthman’s regimes. Instead, they insisted that Ali was Muhammad’s rightful successor: the first imam. This in turn implied an alternative succession, through Hasan and Husayn, then a bloodline of further imams descended from Muhammad.
