The churches of St John and St Mary at Ephesos, 'Building D' at Sardis, St John at Philadelphia, and the basilicas of Hierapolis illustrate the development of vaulted construction on the west coast of Asia Minor between the 5th and the 7th century AD. These churches, due to their dilapidated condition, constitute ideal sources of information about the materials and construction techniques employed in some of the most important building programs of the early Byzantine Empire. The ruined state of the monuments and the lack of written records have hindered attempts to reconstruct their...