The Alids are those who claim descent from Ali ibn Abi Talib, the fourth Rashidun caliph and the first imam in Shia Islam. Ali was also the cousin and son-in-law of the Islamic prophet Muhammad. The main branches are the Hasanids and Husaynids, named after Hasan and Husayn, the eldest sons of Ali from his marriage to Fatima, the daughter of Muhammad. As the progeny of Muhammad, they are revered by all Muslims. The Alids have led various movements in Islam, and a line of twelve Alids are the imams in Twelver Shia, the largest Shia branch.

The Battle of Karbala was fought on 10 October 680 between the army of the second Umayyad caliph Yazid I and a small army led by Husayn ibn Ali, the grandson of the Islamic prophet Muhammad, at Karbala, Sawad.