Complex sentence: Knappertsbusch continued to appear in Vienna and Salzburg after the Nazi-occasioned incorporation of Austria into Germany ('Anschluss'), and conducted in German and Austria as well as in Nazi-occupied and neutral countries throughout the Second World War.
Split into simpler sentences: Knappertsbusch continued to appear in Vienna and Salzburg after the Nazi-occasioned incorporation of Austria into Germany ('Anschluss'). He conducted in German and Austria as well as in Nazi-occupied and neutral countries throughout the Second World War.