Setting the scene
The Anschluss, the annexation of Austria into Nazi Germany, occurred on March 12-13, 1938. The term means 'joining' in German. Austria, reduced to a small state after World War I, had a strong pan-German movement seeking union with Germany, which was prohibited by the Treaty of Versailles and Treaty of Saint-Germain. Hitler, born Austrian, had long sought Anschluss. By 1938, Austrian Nazis, funded by Germany, had destabilized the government of Chancellor Kurt Schuschnigg.
What happened
On February 12, 1938, Hitler summoned Schuschnigg to Berchtesgaden and threatened invasion unless he appointed Nazis to his cabinet. Schuschnigg agreed but then announced a plebiscite on Austrian independence for March 13. Hitler responded by mobilizing troops. On March 11, Schuschnigg resigned under German pressure, and Austrian Nazi Arthur Seyss-Inquart became chancellor. German troops crossed the border on March 12, meeting no resistance and being welcomed by crowds. On March 13, Germany enacted the annexation law.
Why it still matters
The Anschluss was overwhelmingly supported by Austrians—though the subsequent plebiscite on April 10 claiming 99.7% approval was rigged, genuine support was likely 70-80%. Austria became the province of Ostmark. The annexation violated Versailles but Britain and France did nothing, pursuing appeasement. The Anschluss gave Germany 7 million people, Austria's gold reserves, and strategic position for attacks on Czechoslovakia and beyond. It also brought 200,000 Austrian Jews under Nazi rule, leading to immediate persecution. The Anschluss demonstrated the weakness of collective security and emboldened Hitler to demand the Sudetenland later in 1938.
Background
Western powers acquiesced diplomatically.