Greco-Turkish War (1919–1922)
The Greek campaign was launched primarily because the western Allies, particularly British Prime Minister David Lloyd George, had promised Greece territorial gains at the expense of the Ottoman Empire, recently defeated in World War I. The armed conflict started when the Greek forces landed in Smyrna (now Izmir), on 15 May 1919. They advanced inland and took control of the western and northwestern part of Anatolia, including the cities of Manisa, Balıkesir, Aydın, Kütahya, Bursa and Eskişehir. Their advance was checked at the Battle of Sakarya in 1921 by forces of the Turkish national movement. The Greek front collapsed with the Turkish counter-attack in August 1922, and the war effectively ended with the recapture of Smyrna by the Turkish forces and the Great Fire of Smyrna.
Convention of Constantinople (1881)
Greece had remained neutral during the Russo-Turkish War of 1877–78, based on assurances by the other Great Powers that her territorial claims on the Ottoman Empire would be considered after the war. At the Congress of Berlin in 1878, Greece's claims were considered in the Thirteenth Protocol of 5 July 1878, whereby Greece gained not only Thessaly (the Ottoman Sanjak of Tirhala) but also much of Epirus. The Ottoman government, however, refused to implement the protocol's terms, leading Greece and the Empire to the verge of war. In the end, the Great Powers applied pressure on Greece to reduce her claims.