The Great Mosque in Silvan is rectangular in plan, more than twice as wide as it is deep. A central dome surmounts three of the four aisles; the fourth aisle, to the north, is largely a poor reconstruction completed in 1913, and most likely once opened up into a courtyard on the north (which no longer exists).
The cut-stone building dates mainly from the Artukid period of Nadjm ed-Din Alpi, who ruled the area between 1154 and 1176. He rebuilt the dome in 1157 by modeling it on the dome of Malikshah at Isfahan, with a diameter of 13.5 meters. This dome replaces one that was certainly smaller and which related more directly to the three aisles, as the fourth was added at the time the dome was rebuilt. The dome rises above a 16-sided figure; eight squinches octagonal in plan are bisected by an additional eight squinches. The large corner squinches have clumsy decoration; below them are ornate carvings of leaves. All the decoration is heavily influenced by Syrian architecture.
Within the dome is a finely carved mihrab dating to 1227. The exterior is decorated with windows over which are decorated pillars. These would have continued the entire length of the façade; now they are only extant in the original Artukid masonry.
Sources:
Altun, Ara. An outline of Turkish architecture in the Middle Ages. Sirkeci, Istanbul: Arkeoloji ve Sanat Yayinlari, 1990.
Aslanapa, Oktay. Turkish art and architecture. New York: Praeger Publishers, 1971.
Sözen, Metin, and Ilhan Aksit. The Evolution of Turkish Art and Architecture. Istanbul: Has set Kitabevi, 1987.