Upon graduation from the RCM, Britten obtained a position scoring documentaries (on prosaic themes like "Sorting Office") for the Royal Post Office film unit. Working on a tight budget, he learned how to extract the maximum variety of color and musical effectiveness from the smallest combinations of instruments, producing dozens of such scores from 1935 to 1938. He rapidly emerged as the most promising British composer of his generation and entered into collaborative relationships that exerted a profound influence upon his creative life. Among the most important of his professional associates were literary figures like W.H. Auden, and later, E.M. Forster. None, however, played as central a role in Britten's life as the tenor Peter Pears, who was Britten's closest intimate, both personally and professionally, from the late '30s to the composer's death. Pears' voice inspired a number of Britten's vocal cycles and opera roles, and the two often joined forces in song recitals and, from 1948, in the organization and administration of the Aldeburgh Festival.
A steadfast pacifist, Britten left England in 1939 as war loomed over Europe. He spent four years in the United States and Canada, his compositional pace barely slackening, as evidenced by the production of works like the Sinfonia da Requiem (1940), the song cycle Seven Sonnets of Michelangelo (1940), and his first effort for the stage, Paul Bunyan (1940-1941). Eventually, the poetry of George Crabbe drew Britten back to England. With a Koussevitzky Commission backing him, the composer wrote the enormously successful opera Peter Grimes (1944-45), which marked the greatest turning point in his career. His fame secure, Britten over the next several decades wrote a dozen more operas, several of which -- Albert Herring (1947), Billy Budd (1951), The Turn of the Screw (1954), A Midsummer Night's Dream (1960), Death in Venice (1973) -- became instant and permanent fixtures of the repertoire. He also continued to produce much vocal, orchestral, and chamber music, including Songs and Proverbs of William Blake (1965), the three Cello Suites (1961-1964) and the Cello Symphony (1963), written for Mstislav Rostropovich, and the Third String Quartet (1975).
Britten suffered a stroke during heart surgery in 1971, which resulted in something of a slowdown in his creative activities. Nonetheless, he continued to compose until his death in 1976, by which time he was recognized as one of the principal musical figures of the twentieth century.