The name Greco-Turkish War is given to two armed conflicts between Greece and Turkey or its predecessor the Ottoman Empire:
- The Greco-Turkish War of 1897 (also called the Thirty Days' War)
- The Greco-Turkish War of 1919-1922 (also called the War in Asia Minor, the Catastrophe of Asia Minor, and in Turkey part of the Turkish War of Independence)
The Greco–Turkish War of 1919–1922, also called the War in Asia Minor, and in Turkey considered a part of the Turkish War of Independence, was a war between Greece and Turkey fought in the wake of World War I.
This political context of this conflict is linked to secret agreements on sharing of Ottoman Empire at the end of WWI. Military history begins with the Armistice of Mudros. The war arose because the western Allies, particularly British Prime Minister David Lloyd George, had promised Greece territorial gains at the expense of the Ottoman Empire if Greece entered the war on the Allied side. These included eastern Thrace, the islands of Imbros and Tenedos, and parts of western Anatolia around the city of Smyrna (İzmir)
In return to the contribution of the Greek army in the war effort, the 1920 Treaty of Sèvres, which ended the First World War in Asia Minor and in parallel determined the future of the Ottoman Empire, assigned eastern Thrace and the millet of Smyrna to Greece.
Around that time Mustafa Kemal, the leader of a group of Turkish revolutionaries, was forming in Anatolia, the Turkish National Movement. The revolutionaries repudiated the Treaty of Sèvres and prepared for defense of what they believed was their national land given up by the weak Ottoman government to the enemy.
In May 1919, Greek troops landed on Smyrna (İzmir) and occupied the city and the surroundings under cover of French, British and American ships. The Greeks of Smyrna, who were the majority of the city's population, and other Christians greeted the Greek troops as liberators. The Turkish population though saw this as an invading force, as they resented the Greeks and presumably preferred to be under Turkish rule.
The resistance started immediately, mainly by small groups of irregular Turkish troops in the suburbs and the Greeks had many losses. In the summer of 1920, the Greek army, launched successful attacks and extended its zone of occupation over all Western and North Western Asia Minor. Greeks already occupied Eastern Thrace.
In October 1920, with the encouragement of Lloyd George who intended to increase the pressure on the Turkish and Ottoman governments to sign the Treaty of Sevrès, the Greek army advanced further east into Anatolia with the intention of defeating the Kemalist forces before they were ready to attack the Greek perimeter near the coast. They faced little resistance as the Turks were retreating orderly. This advancement begun under the Liberal government of Eleftherios Venizelos, but soon after the offensive began Venizelos fell from power and was replaced by Dimitrios Gounaris, who appointed inexperienced monarchist officers to senior commands. King Constantine took personal command of the army at Smyrna (İzmir).