A folded cross vault is actually built like a regular cross vault but instead of the ribbing that is characteristic of that vault it is typified by fan-like prismatic triangles that are folded inward. The vault’s center point is an octagon where these triangles converge. The folded cross vault first appeared in Jerusalem in the Khanqah Madrasa of Amir Tankiz (1328-1329 CE). After it was built in this madrasa it became popular and occurs in almost every important building in Jerusalem. In Cairo the folded cross vault started to appear at the end of the fourteenth century and was widely used by the fifteenth century.

Research in Islamic art has yet to undertake an in-depth study of the origins of the folded cross vault.

I wish to propose that its design was created in eastern Anatolia where the Iranian Seljuk architecture, which was characterized by mudbrick construction, meets the Christian Anatolian architecture, which was based on stone. The origin of the Mamluk vaults in Jerusalem was probably in the Muslim architecture of Anatolia because such vaults were common there starting in the first quarter of the thirteenth century CE.