Blitzstein 's musical gifts were apparent at an early age ; he had performed a Mozart piano concerto by the time he was seven .
Blitzstein was born in Philadelphia on March 2 , 1905 , to affluent parents .
Blitzstein 's musical gifts were apparent at an early age ; Blitzstein had performed a Mozart piano concerto by the time Blitzstein was seven .
Blitzstein was born in Philadelphia on March 2 , 1905 , to affluent parents .