The occupation of Greece by the Axis powers began in April 1941 after the German invasion of Greece to assist its ally, Italy, in the Greco-Italian War had begun in October 1940. Following the Battle of Crete, Greece was occupied starting in June 1941. The occupation of the mainland lasted until Germany and its ally Bulgaria withdrew under Allied pressure in early October 1944, with Crete and some other Aegean Islands being surrendered to the Allies by German garrisons in May and June 1945, after the end of the Second World War in Europe.