History of Austria
Austria was dominated by the House of Habsburg and House of Habsburg-Lorraine ("Haus Österreich") from 1273 to 1918. In 1808, when Emperor Francis II of Austria dissolved the Holy Roman Empire, Austria became the Austrian Empire, and was also part of the German Confederation until the Austro-Prussian War of 1866. In 1867, Austria formed a dual monarchy with Hungary: the Austro-Hungarian Empire (1867–1918). When this empire collapsed after the end of World War I in 1918, Austria was reduced to the main, mostly German-speaking areas of the empire (its current frontiers), and adopted the name The Republic of German-Austria. However the union and name were forbidden by the Allies at the Treaty of Versailles. This led to the creation of the First Austrian Republic (1918-1933).
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.