Gallipoli (from Greek Kallipolis, Turkish Gelibolu) was always a site of particular strategic importance, as it controlled the Dardanelles straits. Already under the Byzantine Empire, it served as a naval base. The Ottoman Turks first captured the strong fortress from the Byzantines in 1354, along with other sites in the area, aided by an earthquake that collapsed their walls. Gallipoli secured the Ottomans a toehold in the Balkans, and became the seat of the chief Ottoman governor in Rumelia. The fortress was recaptured for Byzantium by the Savoyard Crusade in 1366, but the beleaguered Byzantines were forced to hand it back in September 1376.