The War of Independence and Mustafa Kemal Atatürk 

The Turkish War of Independence[note 3] (15 May 1919 – 24 July 1923) was a series of military campaigns and a revolution waged by the Turkish National Movement, after the Ottoman Empire was occupied and partitioned following its defeat in World War I. The conflict was between the Turkish Nationalists against Allied and separatist forces over the application of Wilsonian principles, especially self-determination, in post-World War I Anatolia and eastern Thrace. The revolution concluded the collapse of the Ottoman Empire and the Eastern question, ending the Ottoman sultanate and the Ottoman caliphate, and establishing the Republic of Turkey. This resulted in the transfer of sovereignty from the sultan-caliph to the nation, setting the stage for nationalist revolutionary reform in Republican Turkey.

While World War I ended for the Ottomans with the Armistice of Mudros, the Allies continued occupying land per the Sykes–Picot Agreement, and to facilitate the prosecution of former members of the Committee of Union and Progress and those involved in the Armenian genocide.[52][53] Ottoman commanders therefore refused orders from the Allies and Ottoman government to disband their forces[citation needed]. In an atmosphere of turmoil, Sultan Mehmed VI dispatched general Mustafa Kemal Pasha (Atatürk), to restore order; however, he became an enabler and leader of Turkish Nationalist resistance. In an attempt to establish control over the power vacuum in Anatolia, the Allies agreed to launch a Greek peacekeeping force and occupy Smyrna (İzmir), inflaming sectarian tensions and beginning the Turkish War of Independence. A nationalist counter government led by Mustafa Kemal was established in Ankara when it became clear the Ottoman government was appeasing the Allies. The Allies pressured the Ottoman "Istanbul government" to suspend the Constitution, Parliament, and sign the Treaty of Sèvres, a treaty unfavorable to Turkish interests that the "Ankara government" declared illegal.

Turkish forces defeated the French in the south, and remobilized army units went on to partition Armenia with the Bolsheviks, resulting in the Treaty of Kars (1921). The Western Front is known as the Greco-Turkish War. İsmet Pasha (İnönü)'s organization of militia into a regular army paid off when Ankara forces fought the Greeks in the First and Second Battle of İnönü. The Greeks emerged victorious in the Battle of Kütahya-Eskişehir and drove on Ankara. The Turks checked their advance in the Battle of Sakarya and counter-attacked in the Great Offensive, which expelled Greek forces. The war ended with the recapture of İzmir, the Chanak Crisis and another armistice in Mudanya.

The Grand National Assembly in Ankara was recognized as the legitimate Turkish government, which signed the Treaty of Lausanne, a treaty more favorable to Turkey than Sèvres. The Allies evacuated Anatolia and eastern Thrace, the Ottoman government was overthrown, the monarchy abolished, and the Grand National Assembly of Turkey declared the Republic of Turkey on 29 October 1923. With the war, a population exchange between Greece and Turkey,[54] the partitioning of the Ottoman Empire, and the abolition of the sultanate, the Ottoman era came to an end, and with Atatürk's reforms, the Turks created the secular nation of Turkey. Turkey's demographics were significantly affected by the Armenian genocide and deportations of Greek-speaking, Orthodox Christian Rum people.[55] The Turkish Nationalist Movement carried out massacres and deportations to eliminate native Christian populations—a continuation of the Armenian genocide and other ethnic cleansing during World War I.[56] The historic Christian presence in Anatolia was largely destroyed; Muslims went from 80% to 98% of the population.[55]