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.
Marburg's Bloody Sunday
The Republic of German Austria was created following the defeat of the Austro-Hungarian Empire in the First World War and claimed areas with a predominantly German-speaking population within the bounds of the former empire. In addition to the current area of the Republic of Austria, these included parts of South Tyrol and the town of Tarvisio, both now in Italy; southern Carinthia and southern Styria, now in Slovenia; and Sudetenland proper and German Bohemia (later also part of Sudetenland), now in the Czech Republic.