ISMA'ILISM

Imam Ja'far al-Sadiq had a son named Isma'il who was the oldest of his children. Isma'il died during the lifetime of his father who summoned witnesses to his death, including the governor of Medina. Concerning this question , some believed that Isma'il did not die but went into occultation, that he would appear again and would be the promised Mahdi. They further believed that the summoning of witnesses on the part of the Imam for Isma'il's death was a way of hiding the truth in fear of al-Mansur, the Abbasid caliph. Another group believed that the true Imam was Isma'il whose death meant the imamate was transferred to his son Muhammad. A third group also held that although he died during the lifetime of his father he was the Imam and that the imamate passed after him to Muhammad ibn Isma'il and his descendants. The first two groups soon became extinct, while the third branch continues to exist to this day and has undergone a certain amount of division.