Background: Samuel Osborne Barber II (March 9, 1910 - January 23, 1981) was an American composer of orchestral, opera, choral, and piano music. He is one of the most celebrated composers of the 20th century: music critic Donal Henahan stated that "Probably no other American composer has ever enjoyed such early, such persistent and such long-lasting acclaim." His Adagio for Strings (1936) has earned a permanent place in the concert repertory of orchestras.
Context: From his early to late twenties, Barber wrote a flurry of successful compositions, launching him into the spotlight of the classical music world. His first orchestral work, an overture to The School for Scandal, was composed in 1931 when he was 21 years old. It premiered successfully two years later in a performance given by the Philadelphia Orchestra under conductor Alexander Smallens. Many of his compositions were commissioned or first performed by such famous artists as Vladimir Horowitz, Eleanor Steber, Raya Garbousova, John Browning, Leontyne Price, Pierre Bernac, Francis Poulenc, and Dietrich Fischer-Dieskau. In 1935, at the age of 25, he was awarded the American Prix de Rome and was the recipient of a Pulitzer traveling scholarship which allowed him to study abroad in 1935-1936. He was later awarded a Guggenheim Fellowship in 1946. When Barber was 28, his Adagio for Strings was performed by the NBC Symphony Orchestra under the direction of Arturo Toscanini in 1938, along with his first Essay for Orchestra. The Adagio had been arranged from the slow movement of Barber's String Quartet, Op. 11. Toscanini had only rarely performed music by American composers before (an exception was Howard Hanson's Second Symphony, which he conducted in 1933). At the end of the first rehearsal of the piece, Toscanini remarked, "Semplice e bella" (simple and beautiful). In 1942, Barber joined the Army Air Corps; there, he was commissioned to write his Second Symphony, a work he later suppressed. (It was released in a Vox recording by the New Zealand Symphony Orchestra conducted by Andrew Schenck.) Composed in 1943, the symphony was originally titled Symphony Dedicated to the Air Forces and was premiered in early 1944 by Serge Koussevitsky and the Boston Symphony Orchestra. Barber revised the symphony in 1947; it was published by G. Schirmer, and recorded the following year by the New Symphony Orchestra of London conducted by the composer, but in 1964 Barber destroyed the score. It was reconstructed from the instrumental parts. According to another source, however, it was precisely the parts to the symphony that Barber had torn up. Hans Heinsheimer was an eyewitness, and reported that he accompanied Barber to the publisher's office where they collected all the music from the library and Barber "tore up all these beautifully and expensively copied materials with his own hands" Doubt has been cast on this story, however, on grounds that Heinsheimer, as an executive at G. Schirmer, would have been unlikely to have allowed Barber into the Schirmer offices to watch him "rip apart the music that his company had invested money in publishing". In 1943, Barber and Menotti purchased a house in Mount Kisco, New York. Barber won the Pulitzer Prize twice: in 1958 for his first opera Vanessa, and in 1963 for his Concerto for Piano and Orchestra. CANNOTANSWER
Question: when was he awarded this?

Answer:

In 1935,