On 19 December 1941, Martinů wrote a letter to Serge Koussevitzky, expressing a wish to compose a symphony for the Boston Symphony Orchestra for their next season. In reply, early in 1942 Koussevitzky commissioned a work for large orchestra in memory of his late wife Natalie. Despite the freedom offered in the commission, Martinů persisted in his intention to tackle the ambitious form of the symphony, with an eye to increasing his standing in American musical life. Work on the Symphony was begun in June with the first movement, in Jamaica. The two middle movements were composed in July in Middlebury, Vermont, and the finale was worked out in July and August, in Lenox, Massachusetts, while Martinů was teaching at the Berkshire Music Center. The score was completed on 1 September 1942, at Manomet, Massachusetts and was premiered on 13 November 1942 in Boston, with further performances in New York on 21 November 1942 and 7 January 1943, all conducted by Serge Koussevitzky.