In an idyllic spot near Salzburg in the summer of 1936, Barber composed his String Quartet in B minor, op. 11. He arranged the slow movement for string orchestra in 1937 in the hopes that Toscanini would perform it during the next season with the NBC Symphony Orchestra. The great conductor did indeed perform it, on November 5, 1938. Titled simply Adagio for Strings, the work has since become Barber’s most popular and frequently performed piece. Often played at funerals, in restaurants, in commercials, and on soundtracks, the Adagio reached a wide audience in the 1986 movie Platoon, though many have suggested that Barber would have objected to its use as the backdrop to such violence.

The movement’s soaring quality is enhanced by the fact that its key (B-flat minor) is never explicitly confirmed; the piece even closes on an open-ended note of resignation. The Adagio’s single, beseeching theme is introduced by the first violin, taken up by each member of the quartet, and built to one of the most sublime climaxes in the repertoire. Following a pause the movement subsides pensively.