The Fatimid Caliphate, the Ismaili Shia dynasty that ruled from Cairo between 969 and 1171, governed a population that was mostly not Ismaili and needed a way to win converts and manage believers scattered far beyond its own borders. It built the dawa, literally the invitation or the summons, a structured missionary hierarchy through which Ismaili teaching was carried, taught in graded stages, and administered across the Muslim world, from Yemen and the Persian lands to Sindh and North Africa.
Rank inside the dawa was formal and hierarchical. Below the Imam himself stood the bab, the gate, and beneath him a chain of ranks that included the hujja, the proof, responsible for a whole region, and the da'i, the working missionary who taught converts directly, examined their readiness for each stage of esoteric instruction, and answered to the rank above him. Further ranks, the ma'dhun and the mukasir, handled preliminary contact and doctrinal argument respectively. The system let the Fatimid dawa operate as an underground movement in regions the Caliphate did not control, since a da'i needed no visible institution to function, only a chain of personal instruction and loyalty running back to Cairo.
The Fatimid state fell in 1171, but the dawa organization it built did not simply disappear with it. Its rank structure, its graded curriculum of esoteric instruction and its principle of a missionary hierarchy answering to a single religious authority became the institutional inheritance that later Ismaili communities, cut off from any ruling Fatimid state, adapted to their own very different circumstances.