Excerpts from Books and Wikipedia
"According to German nationalism, all German-speaking peoples should be united. Hitler, Austrian my birth, made this a reality with the Anschluss (union) of 1938. . . . Hitler demanded that a Nazi government be appointed or he would invade. Schuschnigg resigned and Austrian Nazis took over government offices. On March 12, German army units were welcomed into Austria. A Nazi-controlled referendum gave an endorsement to the union, and Austria became the Ostmark, a province of Greater Germany." [Furtado: 1001 Days]