I'm reading a history of Saladin, and they mention an anecdote in which the Sunni residents of Alexandria rebuffed a request to turn over Saladin's uncle Shirkuh by citing the horror of turning over a Sunni to Shia rulers, and I'm kind of struck by how marked that level of religious opposition to the Ismaili religion of the Caliphate that had governed the region for generations. It seems odd that the Fatimids made virtually no dent in the religious makeup of Egypt during their entire rule. Why was this the case?
Late reply but you should check out Paul E. Walker’s work on Fatimid sermons. Also
Paula Sanders - Ritual, Politics, and the city in Fatimid Cairo
Yacov Lev- State and Society in Fatimid Egypt
Irene Bierman - Writing Signs
Marina Rustow also has some interesting works.
But it boils down to something along the lines of that they did initially try to popularize Ismaili shi’ism in various ways but faced intense opposition from local Sunni jurists and in some instances there was a lot of rioting and backlash against the Ismaili population. One particularly well documented example is when Al-Muiz tried to shut down the market for a shi’i holiday and Sunni merchants rioted.
From the late 10th onwards they preferred a much less vocal and maybe even secretive method of spreading the Ismaili doctrine. In many ways they managed to stabilize their Empire by allowing a lot more “religious freedom” in terms of letting each community choose its own judges/representatives and looked to strengthen Ismaili communities abroad (Yemen is a big example). Really cool moment in history is when the emir of Mosul conducted the Friday prayer in Mosul in the name of the Fatimid caliph.