The monumental complex of Eptapyrgion, the fortress of the citadel, is a work of the Byzantine era, of the imperial dynasty of the Palaiologoi (14th century). The polygonal fortress with its ten towers was rebuilt with stronger walls after the Turkish occupation of the city in 1431. The central tower of the entrance, according to the inscription, was built by Chaouss Bey, who was the first Turkish governor of Thessaloniki. In the late 19th century, the fortress of Eptapyrgion was converted into a prison under the Turkish name of Genti Koule, which was notorious for its cruelty. The use of the fortress as a prison continued under Greek administration until 1989 when they were moved to a modern building. Many prison and rebetiko songs have been written about Genti Koule, and in addition to the criminal inmates, many political prisoners were imprisoned during the Greek Civil War (1946-1949) and the period of the dictatorship (1967-1974). The Eptapyrgion, which has undergone restoration work by the Ministry of Culture, is to house various museum spaces related to the history of the monument.