What is the social background in sound of music film?

The Sound of Music takes place in Austria just before the outbreak of World War II in the mid-1930s and captures the political tension of Europe as Austria begins to fall under a Nazi influence and is about to lose its autonomy to Germany

A strong sense of patriotism amongst the Austrian characters permeates the movie, including Maria’s family and Captain von Trapp's love for country, which he instils in his children