Dodecanese islands were occupied by the French and British, but Rhodes remained under Italian occupation. In 1915, the French also occupied Kastellorizo. Following the war, the Tittoni–Venizelos agreement, signed on July 29, 1919, called for the smaller islands to join with Greece, while Italy maintained control of Rhodes. The treaty further outlined an exchange where Italy would receive Antalya for southwest Anatolia. The Greek defeat in the Greco-Turkish War and the foundation of modern Turkey prevented the exchange. Italy formally annexed the Dodecanese as the "Possedimenti Italiani dell'Egeo" under the terms of the Treaty of Lausanne. Mussolini embarked on a program
Dodecanese campaign when Italian forces recaptured the island of Kastellorizo from British commandos. After the Battle of Greece in April 1941 and the Allied defeat in the Battle of Crete in May 1941, Greece and its many islands were occupied by the Axis powers. With the defeat of Axis forces in the North African campaign in spring 1943, Winston Churchill, the British Prime Minister, who at least as far back as the Gallipoli campaign in World War I had a deep interest in the region, turned his sights on the islands. The British envisaged an operation to capture the Dodecanese and Crete,