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.
Enosis
Thessaly remained under Ottoman control after the formation of the Kingdom of Greece. Although parts of the territory had participated in the initial uprisings in the Greek War of Independence in 1821, the revolts had been swiftly crushed. During the Russo-Turkish War of 1877–78 Greece remained neutral, as a result of assurances by the Great Powers that her territorial claims on the Ottoman Empire would be considered after the war. In 1881 Greece and the Ottoman Empire signed the Convention of Constantinople which created a new Greco-Turkish border, incorporating most of Thessaly into Greece.