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).
Anschluss
Austria remained part of Germany until the end of World War II. A provisional Austrian government declared the "Anschluss" "null und nichtig" (null and void) on 27 April 1945. Henceforth, Austria was recognized as a separate country, although it remained divided into occupation zones and controlled by the Allied Commission until 1955, when the Austrian State Treaty restored its sovereignty.