Before the outbreak of world war 1, Adolf Hitler, who was an Austrian
citizen and was living in Germany at the time, was asked to report to
Salzburg for enlistment in the Austro Hungarian army. He was found to
be unfit for service. After the outbreak of world war 1 Hitler
volunteered for service in a Bavarian regiment which was part of the
German Imperial army. This seems to indicate that the Germans accepted
Austrian citizens to serve in their army.
Henry Wellisch, Toronto <email@example.com>