 Although heavily influenced by architecture from Mesopotamia and Byzantium , the Fatimids introduced or developed unique features such as the four @-@ centred keel arch and the squinch , connecting square interior volumes to the dome . Their mosques followed the hypostyle plan , where a central courtyard was surrounded by arcades with their roofs usually supported by keel arches , initially resting on columns with leafy Corinthian capitals . They typically had features such as portals that protrude from the wall , domes above mihrabs and <unk> , and façade ornamentation with iconographic inscriptions , and stucco decorations . The woodwork of the doors and interiors of the buildings was often finely carved . The Fatimids also made considerable development towards mausoleum building . The <unk> , a shrine that commemorates a descendant of the Prophet Muhammad , was a characteristic type of Fatimid architecture . 
