In the mid-fifteenth century, Sultan Mehmed the Conqueror conquered and united the various tribes and kingdoms of Anatolia and the Balkans, and acquired Constantinople. The Knights of St. John, based in Rhodes had fought the Ottoman Turks for many years; they also withstood the onslaughts of Mehmed II. When sultan Suleiman the Magnificent set out for the conquest of Rhodes, Marmaris served as a base for the Ottoman Navy and Marmaris Castle was rebuilt from scratch in 1522.