Spinalonga, along with Gramvousa and Souda, remained in Venetian hands even after the rest of Crete fell to the Ottomans in the Cretan War (1645–1669) and until 1715, when they fell to the Ottomans during the last Ottoman–Venetian War. These three forts defended Venetian trade routes and were also useful bases in the event of a new Venetian-Turkish war for Crete. Many Christians found refuge in these fortresses to escape persecution from the Ottoman Turks.