Nizar escaped Cairo, rebelled and seized Alexandria, where he reigned as caliph with the regnal name al-Mustafa li-Din Allah (Arabic: المصطفى لدين الله, romanized: al-Muṣṭafā li-Dīn Allāh).
[11][24][25] In order to defend al-Musta'li's succession and counter the claims of Nizar's partisans, al-Mu'stali's son and successor, al-Amir, issued the al-Hidaya al-Amiriyya.
According to the historian Paul E. Walker, sending Abu Abdallah to the strong army of Badr al-Jamali was, if anything, an indication of his high importance and of his father's desire to keep him safe.
When al-Afdal summoned three of al-Mustansir's sons—Nizar, Abdallah, and Isma'il, apparently the most prominent among the caliph's progeny—to the palace to do homage to al-Musta'li, who had been seated on the throne, they each refused.
[28][29] To add to the confusion, having learned of al-Mustansir's passing, Baraqat, the chief missionary (da'i) of Cairo (the head of the Isma'ili religious establishment) proclaimed Abdallah as caliph with the regnal name al-Muwaffaq.
[31] According to Walker, the speed with which Nizar gained support, and some other stories narrated in al-Maqrizi, suggest the existence of a relatively large faction that expected or wanted him to succeed al-Mustansir.
[33] In a surviving letter sent to the Isma'ili Yemeni queen Arwa al-Sulayhi announcing his accession, al-Musta'li gives the "official" version of events as follows: Like the other sons of al-Mustansir, Nizar had at first accepted his imamate and paid him homage, before being moved by greed and envy to revolt.
[34] Problems with succession arrangements had emerged before, but al-Musta'li's accession was the first time that rival members of the Fatimid dynasty had actually fought over the throne.
[35] Given the pivotal role of the imam in the Isma'ili faith, this was of momentous importance: the issue of succession was not merely a matter of political intrigue, but also intensely religious.
In the words of the modern pioneer of Isma'ili studies, Samuel Miklos Stern, "on it depended the continuity of institutional religion as well as the personal salvation of the believer".
[36] To the Isma'ili faithful, writes Stern, it was "not so much the person of the claimant that weighed with his followers; they were not moved by any superior merits of Nizar as a ruler [...] it was the divine right personified in the legitimate heir that counted".
[51] At least one of them, al-Husayn, fled with other members of the dynasty (including three of Nizar's brothers, Muhammad, Isma'il, and Tahir) from Egypt to the western Maghreb in 1095, where they formed a sort of opposition in exile to the new regime in Cairo.
[54][55] The last revolt by a Nizari claimant was by al-Husayn's son Muhammad in 1162, but he was lured with false promises and executed by the vizier Ruzzik ibn Tala'i.
This raised an acute problem for the Nizari faithful, as Isma'ili doctrine held that a line of divinely ordained imams could not possibly be broken.
[1] In the absence of an imam, coinage from Alamut Castle, the centre of Hassan-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.
[58] However, the Nizaris soon came to believe that a grandson (or son) of Nizar had been smuggled out of Egypt and brought to Alamut, and was the rightful imam, living in concealment (satr).
[61][62] Modern Nizari tradition holds that three imams—Ali al-Hadi, Muhammad (I) al-Muhtadi, and Hassan (I) al-Qahir[63][64]—ruled after Nizar while in concealment, but various primary sources give different genealogies.
[65][64] According to the German scholar of Shi'ism, Heinz Halm, the identities of the three concealed imams are most likely fictional,[64] and the veracity of Hasan II's claims to Fatimid descent remain a major historiographical issue.