Answer :
The aftermath of World War I, particularly the peace treaties and the principle of national self-determination, led to the disintegration of land empires and the creation of new nation-states in Europe between 1914-1939.
One significant development in Europe that led to the creation of new states during the period of 1914-1939 was the aftermath of World War I and the subsequent peace treaties. The First World War paved the way for the collapse of several large land empires, most notably the Austro-Hungarian, Russian, and Ottoman Empires. These empires' disintegration at the end of the war allowed for the emergence of new nation-states, as the principle of national self-determination put forth by leaders like U.S. President Woodrow Wilson was applied at the Paris Peace Conference. Notable new countries created included Poland, Czechoslovakia, Austria, Hungary, and the Kingdom of Yugoslavia, which arose from the territories once controlled by the defeated empires.
Additionally, the concept of nationhood and national identity played a crucial role in the formation of these states. The idea that people of similar culture, language, and history should govern themselves led to the re-drawing of Europe's political map. The principle of self-determination was particularly influential -- although not uniformly applied -- as leaders and diplomats attempted to establish borders based on ethnic, linguistic, and historical criteria, often leading to contentious outcomes due to the diversity and mixed populations within the affected regions.
