6. Jaʿfar aṣ-Ṣādiq, son of Muḥammad al-Bāqir.
7. Mūsā al-Kāz̤im, son of Jāʿfar.
8. Ar-Raẓā, son of Mūsā.
9. Muḥammad at-Taqī, son of ar-Raẓā.
10. ʿAlī an-Naqī, son of Muḥammad at-Taqī.
11. Al-Ḥasan al-ʿAskarī, son of ʿAlī an-Naqī.
12. Muḥammad, son of al-Ḥasan al-ʿAskarī, or the Imām al-Mahdī, who is supposed by the Shīʿahs to be still alive, though he has withdrawn for a time, and they say he will again appear in the last days as the Mahdī, or “Director,” which the Prophet prophesied would appear before the Day of Judgment. [[MAHDI].]
The Imāmites trace the descent of this Imām Muḥammad as direct from ʿAlī, thus making him the twelfth lawful Imām, on which account they are called the Is̤nā-ʿasharīyah, or the “Twelveans.” They assert that this last Imām, whilst still a boy, being persecuted by the Abbaside K͟halīfahs, disappeared down a well in the courtyard of a house at Hillah near Bag͟hdād, and Ibn K͟haldun says, so late as even in his day, devout Shīʿahs would assemble every evening after sunset at this well and entreat the absent Imām to appear again on earth.
In the present day, during the absence of the Imām, the Shīʿahs appeal to the Mujtahidūn, or “enlightened doctors of the law,” whose opinion is final on all matters, both temporal and spiritual.
There have been two great schisms in the succession of the Imāms, the first upon the death of ʿAlī Zainu ʾl-ʿAbidīn, when part of the sect adhered to his son Zaid, the founder of the Zaidīyah sect. And the second on the death of aṣ-Ṣādiq, when his father nominated his second son, Mūsā al-Kāz̤im, as his successor, instead of allowing the K͟halīfate to go in Ismāʿīl’s family; those who adhered to Ismāʿīl’s family being called Ismāʿīlīyah. The great body of the Shīʿahs acknowledge Mūsā al-Kāz̤im and his descendants as the true Imāms.