These periods of concealment (dawr al-satr) might end with the renewed public manifestation of the imam, or continue until the present day.
[8][9][10] As a result, the Fatimid-era Isma'ilis accepted the existence of hidden imams (al-a'imma al-masturun) between Muhammad ibn Isma'il and al-Mahdi Billah.
[12] In 1094, on the death of Caliph al-Mustansir Billah, a succession struggle broke out between his sons, the older Nizar being sidelined by the younger al-Musta'li by the machinations of the vizier al-Afdal Shahanshah.
[17] In the absence of an imam, coinage from Alamut Castle, the centre of Hasan-i Sabah's nascent Nizari Isma'ili state in central Persia, was minted with Nizar's regnal name of al-Mustafa li-Din Allah until 1162.
Three such hidden imams are held by modern Nizaris to have lived in Alamut in concealment: Ali al-Hadi, Muhammad (I) al-Muhtadi, and Hasan (I) al-Qahir.
[20] This breach of the father-to-son succession caused a schism in Musta'li Isma'ilism, between those who accepted al-Hafiz (the 'Hafizis'), and those—mostly in Yemen—who upheld the rights of al-Tayyib (the 'Tayyibis').
These truths would be revealed openly during the seventh era, a 'cycle of manifestation' (dawr al-kashf) inaugurated by the qa'im and culminating in the end times.