Following the defeat in World War I, influence of German-speaking elites over Central and Eastern Europe was greatly limited. At the treaty of Versailles Germany was substantially reduced in size. Austria-Hungary was split up. Rump-Austria, which to a certain extent corresponded to the German-speaking areas of Austria-Hungary (a complete split into language groups was impossible due to multi-lingual areas and language-exclaves) adopted the name "German-Austria" (German: Deutschösterreich). The name German-Austria was forbidden by the victorious powers of World War I. Volga Germans living in the Soviet Union were interned in gulags or forcibly relocated during the Second World War.

What greatly reduced the size of Germany after WWI?