The Turkish War of Independence, conducted between 1919 and 1922, aimed to safeguard the territorial integrity within the borders defined by the National Pact after the occupation of the Ottoman Empire by the Allied Powers following its defeat in World War I. It involved a multifaceted political and military struggle against the Greek army in Western Anatolia, the French forces in the south, Armenian forces in the east, as well as loyalist militias, feudal powers, and separatists in Istanbul. The Western Front of this conflict is etched in the Greek national memory as the "Catastrophe of Asia Minor." Throughout the war, Greek and Armenian forces carried out atrocities, lootings, and assaults against the Turkish population as part of an ethnic cleansing operation. The war concluded with the establishment of the Republic of Turkey.
The Greek army, driven by the Megali Idea to unite former Greek territories and prevent Italian occupation, landed in Izmir on May 15, 1919. Dissatisfied with the Armistice of Mudros signed in October 1918, Mustafa Kemal Pasha, seeking ways to liberate the country, arrived in Samsun on May 19, 1919, as the Inspector of the IX Army and initiated a nationwide resistance. At that time, the Straits of Çanakkale and Istanbul, as well as Thrace, were under Allied control; the French occupied Southeast Anatolia and the Mediterranean cities of Mersin, Adana, Kahramanmaraş, Gaziantep, and Urfa; Armenians were occupying Eastern Anatolia and cooperating with French forces in the southeast. Similarly, British troops were present in cities like Eskişehir, Kütahya, and Amasya. Concerned about the potential unrest among the Muslim population, the British Cabinet, considering Lord Curzon's suggestion, decided to propose an American mandate over the region along Anatolia and the Straits on May 19, 1919, aiming to prevent the division of Anatolia and remove Italy and France from the region. Due to the United States' evaluation process of this proposal, peace negotiations were postponed until February 1920. During this period, Mustafa Kemal focused on organizing congresses to spiritually prepare the people for war and to structure the military resistance. He initially planned to slow down the occupation with armed groups formed from the public and, thereby, allow time for the establishment of a regular army. The guerrilla warfare technique with the Kuva-yi Milliye was successful against the French in the south, while on the Eastern Front, the XV Corps under the command of Kazım Karabekir achieved success against Armenian forces.
Thus, under the command of Kazım Karabekir, the army captured Sarıkamış, Kars, and Gümrü, leading to the signing of the Gümrü Treaty on December 3, 1920. On the Western Front, despite the Kuva-yi Milliye forces not being capable of defeating the Greeks, they managed to keep them engaged.
The Greek offensive on the Gediz River on June 22, 1920, highlighted the necessity of a regular army. Meanwhile, King Alexander of Greece died from a monkey bite, leading to the fall of the Eleftherios Venizelos government. Following a referendum, former king Constantine returned from exile to reclaim the throne. As a result of this sudden change, Greece lost all Allied support. Responding to this development on December 9, 1920, Mustafa Kemal relieved Ali Fuat Cebesoy from the command of the Western Front and divided it into north and south, to be commanded successively by Colonel İsmet Bey and Colonel Refet Bey. The suppression of 18 internal uprisings across the country in mid-1920 demonstrated the superiority of the regular army. The reconnaissance attack ordered by Constantine in January 1921 was halted at the First Battle of İnönü. On the other hand, Italy and France, due to their hostile attitudes during World War I, decided to support Turkey against Greece following the return of the king. They requested a revision of the Sevres Treaty. Turkey was invited to the London Conference convened as a result of these requests, enhancing the authority of the Ankara Government nationwide. Realizing they would gain no benefit from the London Conference starting on February 23, 1921, the Greeks launched the Second Battle of İnönü on March 23, resulting in a Turkish victory on April 1.
The Battles of Kütahya-Eskişehir occurred on July 10. After the battle, Afyon, Eskişehir, and Kütahya fell into Greek hands, and the Turkish army withdrew east of the Sakarya River. Following the war, a parliamentary inquiry team was sent to the front by the Grand National Assembly of Turkey (TBMM). After the report from the parliamentary team, National Mobilization orders were issued to meet the equipment needs of the army. Seeking to consolidate their victories, the Greeks, in an attempt to impose the Sevres Treaty, launched an attack on August 23. Although the Greeks approached Ankara within 50 kilometers, the Battle of Sakarya ended in failure for them. Italy, France, and Russia's support for Ankara, along with the embargo imposed on Greece by the Allied Powers after November 1920, worked in favor of the Turks and against the Greeks. To permanently expel Greek forces from Anatolia, Mustafa Kemal Pasha trained his troops for 10 months and made efforts to meet the equipment needs. The offensive, with its overwhelming impact, would ensure success. The attack began on August 26, 1922, and on August 30, the Battle of the Commander-in-Chief's Square resulted in the defeat of Greek forces. The retreating Greek forces were pursued, and the Turkish army entered Izmir on September 9, 1922. By September 18, Greeks had been completely erased from Anatolia. As the Turkish army turned towards the Straits and Istanbul, during the process known as the Çanakkale crisis, Allied forces began withdrawing from Istanbul. Consequently, Greek forces in Thrace also withdrew from the region. The war effectively ended with the Mudanya Armistice signed on October 11, 1922, limited to the Eastern Front by the Kars Treaty signed on October 13, 1921, and conclusively with the signing of the Treaty of Lausanne on July 24, 1923.