an Entity references as follows:
This is a list of the operas performed by Salzburg Festival during the music directorship of Arturo Toscanini and Bruno Walter (1935–1937). This period was ended by the invasion and annexation of the Republic of Austria by Nazi Germany in March 1938. Arturo Toscanini, an avid opponent of the Nazi regime, thereafter declined to return to Salzburg. Bruno Walter was forced to flee to the United States.