Allied-administered Austria

In 1938 the First Austrian Republic had become part of Nazi Germany through an enforced annexation, the Anschluss. The Moscow Declaration of 1943 declared the Anschluss null and void and so set the restoration of an independent Austrian state as one of aims of the Allies. Karl Renner had formed a Provisional Government in late April 1945 and it had, by declaration, separated Austria from Germany. Following the outbreak of peace, this government was very quickly recognised but Austria was still divided into four Allied zones of occupation and Vienna, which was enclosed by the Soviet Zone, was further divided into four, with an additional International Zone at its heart.

The Allied occupation of Austria ended in 1955 and sovereignty was restored via the Austrian State Treaty.

The Vienna Offensive ended on 13 April 1945 with the Soviet capture of Vienna. Western Allied forces reached Austria a couple of weeks later. On 27 April 1945 — almost two weeks before the Nazi surrender on May 8 — Austria was declared independent from the Greater German Empire and the Second Austrian Republic was established.

At the end of the war, Austria and Vienna was divided into 4 zones of occupation, following the terms of the Potsdam Conference. With the permission of the Soviet forces, a provisional government was established in Vienna on April 29 and the first post-war legislative election took place on November 25, 1945. Karl Renner, the first Chancellor of post-World War One Austria, was appointed as Austria's first Chancellor, this appointment lasted until the end of 1945, when Renner became the first President of the Second Republic.

On May 15, 1955, the Austrian State Treaty was signed, officially establishing Austrian independence and sovereignty. The treaty was enacted on July 27 and the last Allied troops left the country on 25 October. On the following day, 26 October, the Declaration of Neutrality was enacted, establishing Austria as a permanently neutral country. For this reason, October 26 is Austria's national holiday.