 The Knights of St. John, or Knights Hospitallers, had captured Rhodes in the early 14th century after the loss of Acre, the last Crusader stronghold in Palestine in 1291.From Rhodes, they became an active part of the trade in the Aegean sea, and at times harassed Turkish shipping in the Levant to secure control over the eastern Mediterranean.A first effort by the Ottomans to capture the island, in 1480, was repulsed by the Order, but the continuing presence of the knights just off the southern coast of Anatolia was a major obstacle to Ottoman expansion.