What is tge source of the divison between sunni and shi'a Muslims.

They both agree on the fundamentals of Islam and share the same Holy Book (The Qur'an), but there are differences mostly derived from their different historical experiences, political and social developments, as well as ethnic composition.

These differences originate from the question of who would succeed the Prophet Muhammad as leader of the emerging Muslim community after his death. To understand them, we need to know a bit about the Prophet's life and political and spiritual legacy.