Diamond composed his Symphony No. 2 in 1942-43, a period of anxiety for the composer as an American whose country was at war and as an artist in lacking a solid financial underpinning. Encouraged by conductor Dimitri Mitropoulos, Diamond sent the score to the Boston Symphony conductor Serge Koussevitzky, renowned for his ongoing support of contemporary music. After a read-through of the symphony, that is to say, not a public performance, the Boston musicians responded with an outpouring of spontaneous applause. The actual première concert performance followed on 22nd October, 1944. In the final year of the war, 1945, Diamond composed Symphonies 3 and 4. Once again, the Boston Symphony music director proved his mettle by persuading the Koussevitzky Foundation to commission the Fourth Symphony. Diamond graciously dedicated the new work to the conductor's late wife, Natalie Koussevitzky. The première took place 23rd January, 1948 with the Boston Symphony, but under Leonard Bernstein, who replaced an indisposed Koussevitzky.