Gaziantep Castle is one of the best examples of surviving castles in Türkiye. It is located in the center of the city, on the southern edge of the Alleben Stream, on a hill that attracts the attention of almost everyone, at an altitude of approximately 25 m, with its magnificence and majesty. There is no definite information about when and by whom Gaziantep Castle was built. It is known that it was founded on a mound whose history goes back 6000 years to the Chalcolithic period and that there was a small city named “Theban” in and around the castle in the II-III centuries A.D.
It was understood as a result of archaeological excavations that the castle was first built as a watchtower in the Roman period in II-IV centuries A.D and expanded over time. It took its current form in the VI century A.D (527-565 A.D) during the period of Byzantine Emperor Justinianus, who was called the "Architect of Castles". Again in this period, the castle underwent an important repair. In order to provide leveling during the repair, the southern section was equipped with substructure (foundation) structures consisting of arched and vaulted galleries, towers connected with these galleries were built, and the city walls were extended to the west, south, and east, up to the border of the hill. In this state, the castle has an irregular circular shape with a diameter of about 100 m and a circumference of 1200 m. There are 12 towers on the castle bodies. Evliya Çelebi mentions the 36 bastions of the Castle in his Travelogue. Today, we can only see 12 of them. It is thought that the remaining 24 bastions were located on the outer walls of the castle and did not survive until today. There was a moat around the castle and the passage to the castle was provided by a bridge. Before you cross the castle bridge and reach the main castle gate, there is a bastion on the left, which is called İmami Gazali's Office by the people. In the years following the Byzantine period, especially Mamluks, Dulkadir principality, and Ottomans repaired the castle from time to time according to the needs and put repair inscriptions about it. The castle was overhauled for the second time in 1481 by the Egyptian Sultan Qaitbay. From the inscription on the main gate, it is understood that the towers on both sides of the main gate and the castle bridge were rebuilt in 1557 by Suleiman the Magnificent during the Ottoman Empire. When you enter through the main castle gate, there are two roads leading to the inner parts of the castle and to the top. You can reach the upper part of the castle from the road that opens to the left. From the road that continues towards its inner parts; the gallery, the corridor, and the castle rooms are reached. There is a water source under the main mass in the castle.