Meryemana Kelisesi, also known by its Syriac name Idto d-Yoldath Aloho (Church of the Mother of God), is a Byzantine era church located in the southwestern quarter of the old walled city of Diyarbakır. The building dates to the sixth century CE but much of the original structure has been lost.
Today, the church consists of a long, high nave terminating on its east end in an apse which is used as a sanctuary. The central portion of the nave is domed. A portico with three arches fronts the church on its west side and opens onto a large paved courtyard. The courtyard is surrounded by private houses, one of which belonged to the former bishop.
The church as it stands is only part of the original building. The sixth century church probably took the form of a triconch with lobes on its north, south, and west sides, and a chancel extending from the east side instead of a fourth lobe. The eastern chancel is what remains today, plus parts of the north and south lobes attached to it. The remains of these can be seen in the curved rear walls of the entrance portico flanking the current portal, which is itself an infilled archway that would have communicated between triconch and chancel.
Sources:
Sinclair, T. A. Eastern Turkey: An Architectural and Archaeological Survey, 184-185. 4 vols. London: The Pindar Press, 1989.