The long period of Fatimid rule, lasting almost three centuries, and the dynasty’s political and ideological principles brought with them a major architectural revival. Clear evidence of change is provided by the monuments of the period, with their many new or additional features deriving from the traditions and cultures of the locations where they were distributed.
Medallion in the tympanum of the Aqmar Mosque, Cairo, 1125. The ribbed, upper part of the arch, over the gateway, contains a circular area with an inscription repeating the name of Muhammad. The name of Ali, the Prophet’s cousin, is at the center. These inscriptions are evidence that the Fatimid dynasty adhered to Shiite doctrine.
via Architecture of the Fatimid | Islamic Arts and Architecture.