At the end of WW1 the Ottoman empire was defeated and in shambles with European armies occupying large parts of it and its capital Constantinople.
With allied troops occupying the Ottoman capital, representatives from the war’s victorious powers signed in 1920 the treaty of Sèvres that divided and partitioned the empire’s lands into European spheres of influence.
The terms of the Treaty of Sèvres were far more severe than those imposed on the German Empire by the Treaty of Versailles.
Sèvres internationalized Istanbul and the Bosphorus, while giving pieces of Anatolian territory to the Greeks, Kurds, Armenians, French, British, and Italians.
It basically turned the Ottoman empire into a small and vulnerable rump country, with a tiny army, with a huge number of ethnically Turkish people displaced out of it and under foreign occupation, while the bosphorus straits and its ancient capital all under the control of European powers and without any direct access to the Mediterranean.
How modern Turkey would've looked like according to the treaty of Sèvres.
The terms of the treaty stirred hostility and nationalist feeling among Turks all across the Ottoman empire, and one man rose up to lead the Turkish resistance against it, that man was Mustafa Kemal Atatürk , the father of modern day Turkey.
Atatürk (In fact, the surname "Atatürk", was given to him by the Turkish Grand National Assembly, literally means “the father of Turks.”) was already considered a war hero in Turkey by that time. His exploits in leading the Turkish army and defending Turkey against a combined British and Australian amphibious invasion at the Dardanelles in 1915 had already made him a celebrated and nationally respected figure in Turkey.
Atatürk, along with a group of other like minded Turkish nationalists, intended to fight back at the foreign occupying armies in Turkey, repudiate Sevrés and create a nationalist modern secular republican Turkey.
Atatürk became the leader of the Turkish National Movement. He established a provisional government in present-day Turkish capital Ankara and launched an nationwide armed revolt against the treaty of Sèvres and the partitioning of Turkey.
Mustafa Kemal Atatürk.
The European powers looked down and took no heed of Atatürk and the Turkish nationalists, thinking that they will soon be crushed and the revolt will quickly dissipate. However events would turn out quit differently than how the European powers expected them to turn.
At first it seemed that the Turkish nationalists would be quickly defeated by the Greek army and their European allies, who had the Turkish nationalists on the run, but soon the tides of war would turn and it would be the Greeks who would be fleeing the Turks, all the way back to Greece.
Atatürk would go on to lead the Turkish nationalists armies and defeat all the combined armies of the signatories of the Treaty of Sèvres, and expell all foreign occupying forces out of Turkey.
The Turkish nationalists victory, in what became known as the war of Turkish independence, forced the European powers to annul the Sèvres treaty and draft a new one, this one taking into consideration the wishes of Atatürk and the Turkish people.
This led to a new treaty, the 1923 Treaty of Lausanne, in which Turkish sovereignty was preserved through the establishment of the modern-day Republic of Turkey.
Ataturk proclaims the establishment of the Turkish republic in the Grand Assembly in 1923.
In many ways the treaty of Sèvres was the trigger that set into motion the Turkish nationalist movement and a whole series of events that culminated in the creation of modern day Turkey.
The legacy of Atatürk's and Turkish nationalists, their war of Independence and the successful resistance to European imperialist powers is a source of national pride in Turkey that extends to this day, and modern day Turkey is built around the achievements of Mustafa Kemal Atatürk.
William L. Cleveland , "A History of the Modern Middle East."
Patrick Balfour Kinross, "Ataturk: A Biography of Mustafa Kemal, Father of Modern Turkey."