The balance between Sunni and Shiah Islam changed dramatically at the beginning of the fourth/tenth century with the rise to power of the Fatimids in North Africa and with the success of related movements, such as the Qarmatians, in other provinces of the Muslim empire. For a while Shiism enjoyed an ascendancy that eventually culminated in the latter part of the same century with Buyid control of Baghdad, Hamdanid domination in Aleppo and Fatimid rule in Cairo. Each of these movements espoused a form of Shiite religious ideology. Unfortunately, while the superficial facts of these political developments are available in the standard Arabic chronicles, the underlying doctrinal theories of these and other Shiite groups of the period are not. A complete account of Shiism ought to include details of the thoughts and activities of its partisans, especially those with a claim to positions of influence and leadership. However, the literature of Shiism, as well as its authors, from the critical turning point in the sect's history continue to exist in obscurity.

The theoretical concepts involved tend to be clear enough. Shiism, in direct contrast to Sunnism, holds that there necessarily exists a divinely ordained, supreme human authority in all religious matters. During his lifetime, the prophet occupied this office: his ruling on any issue was for all intents and purposes that of God Himself.