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 territory in Asia Minor the administration of Smyrna and its hinterland as a protectorate for five years , after with a referendum could decide whether it would remain in the Ottoman Empire 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
Greek genocide
Greek genocide
Megali Idea