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).
Germany
In 1871, Germany became a nation state when most of the German states (most notably excluding Switzerland and Austria) unified into the Prussian-dominated German Empire. After World War I and the revolution of 1918–19, the Empire was replaced by the parliamentary Weimar Republic. The Nazi seizure of power in 1933 led to the establishment of a dictatorship, the annexation of Austria, World War II, and the Holocaust. After the end of World War II in Europe and a period of Allied occupation, Austria was re-established as an independent country and two new German states were founded: West Germany, formed from the American, British, and French occupation zones, and East Germany, formed from the Soviet occupation zone. Following the Revolutions of 1989 that ended communist rule in Central and Eastern Europe, the country was reunified on 3 October 1990.