After the Fatimid rise to power, the caliph
al-Mahdi founded the capital, al-Mahdiyya, in 308 / 914, adopting an innovative town plan that reflected the centrality of the Shi‘ite caliph
according to the Fatimid world view, a view that thenceforth affected the appearance of all Fatimid cities. The mosque
, once at the very heart of urban living, gave way to the splendidly decorated, multi-storey palace of the caliph
who was both political leader and spiritual figurehead of the Fatimid dynasty; it was he who now occupied the very heart of the city, his palace placed at the centre of the kasbah
(citadel) and overlooking the main mosque
near the city walls.