The result of the Ottoman Empire's downfall after World War I was the emergence of new nation-states and significant territorial realignment in the Middle East and Southeastern Europe. Following the war, the Treaty of Sèvres in 1920, and later the Treaty of Lausanne in 1923, formally dismantled the empire, leading to the establishment of the Republic of Turkey under Mustafa Kemal Atatürk. The collapse also instigated a power vacuum, leading to nationalist movements and conflicts in the region, including the Kurdish struggle for autonomy and the complexities that would contribute to ongoing geopolitical tensions in modern times.