- Germany: Germany was defeated in World War I and lost much of its territory, including Alsace-Lorraine to France, Eupen-Malmédy to Belgium, North Schleswig to Denmark, and West Prussia, Posen, and Upper Silesia to Poland. Germany also lost all of its overseas colonies, and its military was severely restricted.
- Austria-Hungary: Austria-Hungary was dissolved into several smaller countries, including Austria, Hungary, Czechoslovakia, Yugoslavia, and Romania.
- The Ottoman Empire: The Ottoman Empire was dismantled, and its territories were divided among the Allied Powers. Turkey was established as a new state, but it was much smaller than the Ottoman Empire.
- Russia: Russia was defeated in World War I, and its government was overthrown by the Bolsheviks in 1917. The new Soviet Union was a much smaller country than the Russian Empire, and it was not a major power until after World War II.