Austrians
Historically, Austrians were regarded as ethnic Germans and viewed themselves as such. Austria was part of the Holy Roman Empire and the German Confederation until the Austro-Prussian war in 1866 which resulted in Prussia expelling Austria from the Confederation. Thus, when Germany was founded as a nation-state in 1871, Austria was not a part of it. In 1867, Austria was reformed into the Austro-Hungarian Empire. After the collapse of the Austro-Hungarian Empire in 1918 at the end of World War I, Austria was reduced to a rump state and adopted and briefly used the name the Republic of German-Austria ("Republik Deutschösterreich") in an attempt for union with the Republic of Germany, but was forbidden due to the Treaty of Saint-Germain-en-Laye (1919). The First Austrian Republic was founded in 1919. The Third Reich annexed Austria with the "Anschluss" in 1938.
1938 Austrian Anschluss referendum
After the end of World War I, the newly founded Austria, which claimed sovereignty over the majority-German territory of the former Habsburg empire. According to its provisional constitution it declared to be part of the also newly founded German Republic. Later plebiscites in Tyrol and Salzburg in 1921, where majorities of 98,77% and 99,11% voted for a unification with Germany, showed that it was also backed by the population.