The disintegration of the Ottoman Empire after World War I was driven by a combination of military defeat, nationalist movements, and external pressures from foreign powers. The war devastated Ottoman territories, leading to immense losses and economic hardship. Independence movements, particularly among Arab and Balkan populations, sought self-determination, further weakening the empire. The Treaty of Sèvres (1920) imposed harsh terms on the Ottomans, leading to territorial losses and the eventual rise of Mustafa Kemal Atatürk, who established the Republic of Turkey in 1923, effectively marking the end of the Ottoman Empire and beginning a new era in Turkish history.