The Austro-Hungarian Empire collapsed in 1918 with the end of World War I. The First Austrian Republic was established in 1919. In the 1938 Anschluss , Austria was occupied and annexed by Nazi Germany. This lasted until the end of World War II in 1945, after which Austria was occupied by the Allies and its former democratic constitution was restored. In 1955, the Austrian State Treaty re-established Austria as a sovereign state, ending the occupation. In the same year, the Austrian Parliament created the Declaration of Neutrality which declared that the country would become permanently neutral.
The Napoleonic Wars were the cause of the final dissolution of the Holy Roman Empire, and ultimately the cause for the quest for a German nation state in 19th-century German nationalism . After the Congress of Vienna , Austria and Prussia emerged as two competitors. Austria, trying to remain the dominant power in Central Europe, led the way in the terms of the Congress of Vienna. The Congress of Vienna was essentially conservative, assuring that little would change in Europe and preventing Germany from uniting.  These terms came to a sudden halt following the Revolutions of 1848 and the Crimean War in 1856, paving the way for German unification in the 1860s. By the 1820s, large numbers of Jewish German women had intermarried with Christian German men and had converted to Christianity.  Jewish German Eduard Lasker was a prominent German nationalist figure who promoted the unification of Germany in the mid-19th century.