Qasr Kharana, Jordan
The room is lined with Umayyad inscriptions (blind arch, photo right), of the form "So-and-So was here." These help to date the structure, and hint at its possible use as a guest house. The dome is placed on squinches (far corner of room, semicircular arch spanning the corner beneath the dome), an innovative treatment that was extensively developed in later Islamic architecture. Its purpose is to provide a graceful transition between the circular dome and the square room beneath it.