ISMAIL, son of Jafar Sadaq, was the seventh Imam of the Shiah Muhammadan. The Shiah sect look on All as the first rightful leader of the .Muhamtnadans, and say him and his wife Fatima, Mahomed's daughter, have alone sprung the rightful heirs to the Imamat. In this view, Abubakr, Umar, and Othman, who pre ceded Ali, and Mudwiyah, the fifth khalif, and his son Yezid, are all alike regarded as usurpers. Ali, Hasan, and Husain were first, second, and third. Jafar, the sixth of the Shiah Imams, was a man of superior sanctity, wisdom, and learning. He was the author of the Book of Faith which is still in use. A tradition exists that he did not die, and will reappear. His son Ismail was, during his lifetime, nominated his successor, but, dying before his father, and leaving none but young children, his half-brother Musa ICasim, whose mother was a slave, was elected to the Inalimat.
Mesa's son AE was eighth Imam ; Muhammad bin-Ali was ninth ;* Ali, son of Muhammad, tenth ; Hasan, the eleventh, was poisoned, and his son Muhammad, born A.H. 255 at Sermenrai, and who was a mere infant at his father's death, was his successor, but disappeared mysteriously at the age of twelve years. According to a legend, he entered a cave at Sermenrai, near Baghdad. On the accession of Musa Kasim, many of Ismail's followers espoused the cause of his children, and formed a sect, who became notorious in history as the Assassins, their ruler being styled the Shaikh ul-Jabl, or Old Man of the Mountain, whose fortress was Alamut ; but with the defeat of Kahir Shah, Ala-nd-Din's son, the demolition of his strongholds, and the slaughter of over 12,000 of his adherents by Hulaku, the power of the Ismaili family came to an end.