This project investigates the radical shift in the architectural shape of the Byzantine church in the Eastern Mediterranean, from a long basilica to a compact, centrally-planned building crowned by a dome. The researchers hypothesize that the reason for this shift was the creation of a new type of space that could acoustically enhance a ritual performance that was primarily chanted - a reason that has never been explored before. The investigation focuses on the transformation and development of the Byzantine church as a performance space by analyzing architectural changes, acoustical properties, the development of chant, and the introduction of decorative themes that are related to music and ritual setting, in a set of buildings from the 9th - 15th century. Data obtained from this study will have the added benefit of enabling musicologists and sound engineers to create sound spaces within studios that mimic the sonic dimensions of actual Byzantine settings. The data will also be used in support of an NSF grant proposal to produce a study of medieval psychoacoustics.