Original: The piece was written in 1943, the score being inscribed "15 August - 8 October 1943", and it premiered on December 1, 1944 in Boston Symphony Hall by the Boston Symphony Orchestra conducted by Serge Koussevitzky.
Simplified: The work was written in 1943 and it was first performed on 1 December  1944 in the Boston Symphony Hall by the Boston Symphony Orchestra with the conductor Serge Koussevitzky.