The Old Mosque (Eski Camii) was built in the early 15C by the architect Haci Alaeddin. Despite its massive appearance – a square with 50m-long sides – it retains a certain grace. The small minaret on the left is probably original, while the second, somewhat more ornate, dates from the 16C. It is recognisable by its two balconies, supported by attractive stalactite corbels. The interior is divided into three naves, each crowned by a cupola. Gigantic black calligraphy ornaments the walls.