The Great Mosque of Diyarbakır The Great Mosque of Diyarbakır is a historically significant mosque in Anatolia, believed to be the oldest of its kind. Following the Muslim conquest of Diyarbakır in 639, a church in the city was temporarily used as a mosque. It was later rebuilt by Seljuk Sultan Malikshah between 1091-1097 CE (484 AH), as indicated by an inscription on site. The mosque underwent numerous changes over the years due to natural disasters and subsequent building campaigns by rulers, resulting in its current form. The mosque features a rectangular courtyard measuring 63 x 30 meters, bounded by an arcade on the east and west sides, later structures on the north side, and a single-aisled prayer hall on the south side. Additionally, a large public space paved with stone now adjoins the mosque's portal and former entrance door. Notably, several features of the Diyarbakır mosque bear a striking resemblance to Damascus' Umayyad Mosque, which was constructed over half a century earlier. The proportions of both prayer halls are remarkably similar, as are their entrances and layouts. Given the Umayyad Mosque's status as one of Islam's earliest mosques, it is no surprise that its design served as inspiration for numerous copies. In 1115/509 AH, the Great Mosque of Diyarbakır underwent renovations following a fire and earthquake. Inscriptions from 1117-1118/511 AH on the west side of the courtyard and an inscription from 1162/557 AH on the east side indicate the dates of several of these renovations. The mosque was constructed using both local basalt blocks and materials from Byzantine buildings that were repurposed. Notably, antique columns, capitals with vine scroll ornamentation, and fragments of Greek inscriptions were used in the construction of the mosque, showcasing the use of spolia in the area. In 1890, an octagonal ablution fountain was added to the center of the mosque's courtyard. Today, the Ulu Mosque remains a notable monument in Anatolia, featuring two theology schools and other structures in the surrounding area.