On 24 July 1923 the Treaty of Lausanne was signed there in Switzerland to settle disagreements over the breakup of the Ottoman Empire and the establishment of modern Turkey and Greece and Bulgaria, etc.
An earlier attempt to pick apart the empire at Sevres in 1920 was never ratified, and in this newer treaty Turkey gained and Greece lost territory and resources.
https://en.wikipedia.org/wiki/Treaty_of_Lausanne
British and French pursuit of corporate interests in this period set in motion problems that continue to this day, not least involving Kurdish politics and the Greek economy.
Treaty negotiations were very complicated: https://en.wikipedia.org/wiki/Lausanne_Conference_of_1922–1923