Sunni and Shia Muslims disagree on the rightful successor to the Prophet Muhammad. Sunnis believe that Abu Bakr, a close companion of the Prophet, was the rightful successor, while Shias believe that Ali, the Prophet's cousin and son-in-law, should have been the first caliph. This disagreement has led to differences in religious practices, theological beliefs, and interpretations of Islamic history. Additionally, there are differences in some religious practices and rituals, such as the commemoration of Ashura and the role of religious leaders.
