This period was followed by the Major Occultation (941–present), where there is no agent of the Hidden Imam, whose reappearance is expected by the Twelvers to fill the earth with justice and peace in the end of time.
[13] Tabatabai suggests that these restrictions were placed on al-Askari because the caliphate had come to know about traditions among the Shia elite, predicting that the eleventh Imam would father the eschatological Mahdi.
[16] By the time of Muhammad al-Jawad, the ninth Imam, some of the representatives took administrative and military roles in the caliphate by practicing religious dissimulation (taqiya).
[24] A Shia tradition attributed to the sixth Imam, Ja'far al-Sadiq, states that this threat was specific to Muhammad al-Mahdi, who was expected to rise, unlike his predecessors who practiced religious dissimulation (taqiya) and were politically quiescent.
[25][26] Twelver sources detail that al-Mahdi made his only public appearance to lead the funeral prayer for his father instead of his uncle, Ja'far.
[27][28] It is also said that the occultation took place in the family home in Samarra, where currently a mosque stands, under which there is a cellar (sardab) that hides a well (Bi'r al-Ghayba, lit.
[36][23] Abu Ja'far, who served for some forty years, has been credited with the unification of the mainstream Shia behind the son of al-Askari as the twelfth Imam in concealment.
[40] The letter, ascribed to al-Mahdi, added that the complete occultation would continue until God granted him permission to manifest himself again in a time when the earth would be filled with tyranny.
[33][45] Sachedina suggests that the later stress of the Twelver literature on the four deputies (al-nuwwab al-arba'[42]) was likely due to their prominence in Baghdad, the Shia center of the time.
[46] For instance, Abu Ja'far Muhammad ibn Ali al-Shalmaghani turned against al-Nawbakhti and claimed to be the rightful agent of al-Mahdi, before denouncing the concept of occultation as a lie.
[58][60] Ibn Babawayh (d. 991) suggested that the situation remains unknown until the reappearance of al-Mahdi but also added that the large population of the Shia did not necessarily guarantee his safety.
[65] In this period, possibly after 295 (908), Shia traditionists also settled the number of Imams with the help of a Sunni hadith, in circulation long before the occultation, which stated that the prophet would be followed by twelve successors.