The first construction date of the citadel is not known, but is thought to have been constructed by the Byzantines in the first half of the 5th century A.D. The citadel is surrounded by an outer citadel on the hill it is located at. Today, the outer citadel, which has a dual arrangement is ruined at a large scale and only the name remains of the doors which opened in four directions. These gates are Erzincan Gate, Tebriz Gate, Gürcü Gate, İstanbul Gate and New Gate (Yenikapi) founded later. There are eight towers on the walls of the Inner Citadel. It is possible to observe the restoration traces on the Citadel walls at the different periods. However, there are no inscriptions belonging to these periods.