The first known performance of this song (to date) is 14 Oct 1943, but the song is drafted on the same paper type as the folk songs first performed on 11 Dec 1940, so it is logical to assume it was written at around the same time.
Meg Mundy (b.1915). American Actress, and daughter of John and Clytie Mundy, professional cellist and singer respectively. Britten and Pears knew the family during their stay in New York.