Following the Greek gains in the Balkan Wars, the Ottomans began to persecute ethnic Greeks living in the Empire, which led to ethnic cleansing in the Greek genocide. This persecution continued into World War I when the Ottomans declared for the Central Powers on late 1914. Greece remained neutral until 1917 when they joined the Allies. Refugees reports of Turkish atrocities as well as the Allied victory in World War I seemed to promise an even greater realization of the Megali Idea. Greece gained a foothold in Asia Minor with a protectorate over Smyrna and its hinterland. Following 5 years of Greek administration, a referendum was to be held to determine whether the territory would revert to Ottoman control or join Greece. Greece also gained the islands of Imbros and Tenedos, Western and Eastern Thrace, the border then drawn a few miles from the walls of Constantinople.