Musa al-Kadhim

The largest permanent division within Shia Islam happened at the death of Musa's father, Jafar al-Sadiq, in 765, and it happened because the expected heir was already dead.

Ismail, Jafar's eldest son, had been widely understood to be designated, and he predeceased his father. What followed was not one dispute but several running at once. Some held that the designation could not be revoked and passed to Ismail's son Muhammad, and from that position the Ismaili tradition developed, later producing the Fatimid caliphate and, in time, the Nizari and Tayyibi communities. Others followed Musa, and that line, continuing through his descendants to the twelfth imam, is Twelver Shi'ism, today much the largest Shia body. Smaller groupings followed other sons, and one, the waqifiyya, held that Musa himself was the awaited mahdi and had not died at all.

The doctrinal issue underneath is what designation means. If the imamate passes by an explicit appointment that carries divine knowledge with it, an appointment cannot simply be corrected by events, and the alternative is to say that the appointment was never what people took it to be. Both branches had to answer that, and their answers are among the earliest sustained pieces of Shia theology.

The claim that Musa had not died was persistent enough that the circumstances of his death in custody in Baghdad in 799 were handled with the dispute in mind: reports describe the body being displayed publicly before burial specifically so that nobody could maintain he was still alive.

Musa held the imamate through the height of Abbasid power, under rulers whose claim to authority rested on descent from the Prophet's family and who therefore treated a rival claimant within that family as a direct threat. His response was quietist. He made no bid for power, taught within a restricted circle, and made extensive use of the principle that a believer under threat may conceal his position.

The institutional development attributed to his period is the network of agents. Representatives in Kufa, Baghdad, Egypt and the Iranian provinces collected the religious levy from followers, transmitted questions and rulings, and maintained contact with an imam who was frequently under surveillance or in custody. That arrangement outlasted him and became the framework through which the community was administered during the later imamates and, after them, during the concealment of the twelfth imam. A community that could function without direct access to its leader had to build the means, and this is where the means were built.

He was arrested more than once and died in 799 in Baghdad while held by the authorities. The tradition holds that he was poisoned; the reports name officials and vary in detail, and no version is independently confirmed.

He was buried in a cemetery north of Baghdad which grew into the town and shrine of Kadhimiya, where his grandson Muhammad al-Jawad, the ninth imam, is buried beside him. Successive dynasties rebuilt and enlarged the complex, and it remains one of the principal places of Shia pilgrimage, standing inside what is now the city of Baghdad itself.