Shia Islam (/ ˈʃiːə /) is the second-largest branch of Islam. It holds that the Islamic prophet Muhammad designated Ali ibn Abi Talib (656–661 CE) as his successor (Arabic: خليفة, romanized:khalifa) and the Imam (Arabic: امام, lit. 'spiritual and political leader') after him, most notably at the event of Ghadir Khumm, but was ...