The Twelve Imams In Shia Doctrine

Twelver Shia Islam, the majority branch of Shia Islam, holds that leadership of the Muslim community after the Prophet Muhammad's death rightfully belonged to his son-in-law and cousin Ali ibn Abi Talib and, through him, to a designated line of eleven further descendants known as the Imams. Where Sunni Islam holds that Muhammad's successors, the caliphs, were chosen by the community, Twelver doctrine holds that each Imam was explicitly designated (nass) by his predecessor and possessed special spiritual authority and infallibility (isma) in interpreting the Quran and Islamic law, distinguishing the Imams sharply from ordinary political rulers.

The line runs from Ali, assassinated in 661, through his sons Hasan and Husayn, the latter killed at the Battle of Karbala in 680 in an event of central importance to Shia religious identity and mourning practice, and continues through nine further generations to Hasan al-Askari, the eleventh Imam, who died in 874. Several of the Imams lived under close surveillance or house arrest by Sunni caliphal authorities who regarded their claim as a political threat, and Shia tradition holds that a number were killed by poisoning at the instigation of the ruling caliphate.