For Shiite Muslims, an imam is central in defining their beliefs. In contrast, for Sunni Muslims, an imam is simply the local cleric who leads the five daily prayers or an honorific title for a scholar.

The Creation of the Caliphate

The roots of a Shiite imam go back to the original Sunni/Shiite split.

Ali, Muhammad’s cousin and son-in-law (through his daughter, Fatima), became the Prophet Muhammad’s first male convert to Islam. When Muhammad died in 632, he had been both the political and spiritual leader of nearly all of the Arabian Peninsula. His successors, the caliphs, would take on the same role. The first three caliphs were outside of Muhammad's bloodline and the third of these was killed by rebellious troops in 656.

Ali Takes Center Stage

After taking office, Ali declined to punish the previous caliph’s murderers and undid many of his acts. Ali also transferred the capital from Medina, in Arabia, to Kufa, in what is now Iraq. An anti-Ali coalition began to form and marched an army north to challenge Ali but was soundly defeated. However, the governor of Syria, Mu'awiya, nephew of the former caliph, refused to follow Ali's order to abdicate his governorship. Things went downhill for Ali in his conflict with Mu'awiya. He lost much of his power base, eventually dying in Kufa at the hands of one of his former soldiers in 661.

The Split Between Sunni and Shiite

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Those who would later be called Shiites believed that Ali was second only to Muhammad and a sacred imam. His son by Fatima, Hasan, and the second Shiite imam, ruled briefly before being ousted by Mu'awiya. Another of Ali's sons by Fatima, Husayn, claimed the right to rule but died in an ambush at Karbala in Iraq in 680. Mu'awiya assumed the caliphate, but Shiites viewed him and his successors as illegitimate. Husayn was the third imam, and every year, Shiites recreate his death in the Ashura ceremonies.

The Shiite Concept of Imam

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Since the death of Husayn, there have been numerous other imams. The various sects of Shiite Islam have different views of who were imams after Husayn. For all Shiites, the imams are direct descendants of Ali and Muhammad through Fatima. Many Shiites are "Twelvers" who believe in twelve imams. The last Imam, they believe, left earth in 874 and is hiding until he returns as the messiah (or mahdi) with the Prophet Jesus and initiates the day of judgment. Ayatollahs have since been the spiritual leaders of Shiites. For most Shiites, the imams were transmitters of secret, sacred knowledge going back to Ali. This particular reverence for imams of Ali's line is main distinguishing feature that separates Shiites from Sunnis.