Renaissance Research "Conservatory Project" Pop Quiz: Which Composer Began A Choral Work On This Day Seventy Years Ago When The Nazis Invaded Poland?

[Click on image for enlargement.]

Hint: The composer was an American.

Header photo: The Thomas-Mann House in Nida, Lithuania, Present Day European Union. German writer Thomas Mann and his family spent three consecutive summers in Nida from 1930-1932. In 1995 the Thomas Mann Cultural Center was established in the house and it became a museum. (c) Igor Sarembo and the European Press Agency. Copyright controlled. Via the European Commission Enlargement Archive.