What was the historical divide between Sunni and Shiite Muslims based on?

The historical divide between Sunni and Shiite Muslims fundamentally emerged from disagreements regarding the rightful succession of leadership after the death of the Prophet Muhammad in 632 CE. This pivotal event raised critical questions over who should be considered his legitimate successor. Those who became known as Sunnis believed that the community should select the leader (caliph) based on consensus and merit, leading to the election of Abu Bakr, a close companion of Muhammad. On the other hand, the Shiite faction argued for a direct lineage succession, insisting that leadership should remain within the Prophet's family, specifically favoring Ali, Muhammad's cousin and son-in-law. This fundamental disagreement over succession created two distinct branches of Islam, shaping theological, political, and cultural identities that persist to this day.

The other options, while they may relate to practices or beliefs within the broader context of Sunni and Shiite Islam, do not capture the original cause of the divide as effectively as the question indicates. Differences in ritual practices, theological interpretations, and territorial claims developed later in the historical narrative and stemmed from the initial division over leadership.