During the conversion a part of the apse was removed and a niche (mihrap) built showing the direction of Mecca. A minaret and medresse were also added. With the beginning of the Republic era the mosque became a museum and the American Byzantine Institute uncovered the frescoes and mosaics inside in 1955. The arch built by the Turks was replaced by columns as originally found. In the 1960's the mosque was once again opened for worship. The walls of the mosque are a mix of stone and bricks. The Greek inscriptions on the exterior walls and interior mosaics are particularly eye-catching.
