was a social, political and religious leader. The grandson of the Islamic prophet Muhammad and a son of Ali ibn Abi Talib and Muhammad's daughter Fatima, as well as a younger brother of Hasan ibn Ali,[9] Husayn is regarded as the third Imam (leader) in Shia Islam after his brother, Hasan, and before his son, Ali al-Sajjad. Being the grandson of the prophet, he is also a prominent member of the Ahl al-Bayt. He is also considered to be a member of the Ahl al-Kisa and a participant in the event of the mubahala. Muhammad described him and his brother, Hasan, as the leaders of the youth