Background: Wystan Hugh Auden (21 February 1907 - 29 September 1973) was an English-American poet. Auden's poetry was noted for its stylistic and technical achievement, its engagement with politics, morals, love, and religion, and its variety in tone, form and content. He is best known for love poems such as "Funeral Blues", poems on political and social themes such as "September 1, 1939" and "The Shield of Achilles", poems on cultural and psychological themes such as The Age of Anxiety, and poems on religious themes such as "For the Time Being" and "Horae Canonicae." He was born in York, grew up in and near Birmingham in a professional middle-class family.
Context: Auden was born in York, England, to George Augustus Auden (1872-1957), a physician, and Constance Rosalie Auden (nee Bicknell; 1869-1941), who had trained (but never served) as a missionary nurse. He was the third of three sons; the eldest, George Bernard Auden (1900-1978), became a farmer, while the second, John Bicknell Auden (1903-1991), became a geologist.  Auden, whose grandfathers were both Church of England clergymen, grew up in an Anglo-Catholic household that followed a "High" form of Anglicanism with doctrine and ritual resembling those of Roman Catholicism. He traced his love of music and language partly to the church services of his childhood. He believed he was of Icelandic descent, and his lifelong fascination with Icelandic legends and Old Norse sagas is evident in his work.  In 1908 his family moved to Homer Road, Solihull, near Birmingham, where his father had been appointed the School Medical Officer and Lecturer (later Professor) of Public Health. Auden's lifelong psychoanalytic interests began in his father's library. From the age of eight he attended boarding schools, returning home for holidays. His visits to the Pennine landscape and its declining lead-mining industry figure in many of his poems; the remote decaying mining village of Rookhope was for him a "sacred landscape", evoked in a late poem, "Amor Loci". Until he was fifteen he expected to become a mining engineer, but his passion for words had already begun. He wrote later: "words so excite me that a pornographic story, for example, excites me sexually more than a living person can do."  Auden attended St Edmund's School, Hindhead, Surrey, where he met Christopher Isherwood, later famous in his own right as a novelist. At thirteen he went to Gresham's School in Norfolk; there, in 1922, when his friend Robert Medley asked him if he wrote poetry, Auden first realised his vocation was to be a poet. Soon after, he "discover(ed) that he (had) lost his faith" (through a gradual realisation that he had lost interest in religion, not through any decisive change of views). In school productions of Shakespeare, he played Katherina in The Taming of the Shrew in 1922, and Caliban in The Tempest in 1925, his last year at Gresham's. His first published poems appeared in the school magazine in 1923. Auden later wrote a chapter on Gresham's for Graham Greene's The Old School: Essays by Divers Hands (1934).  In 1925 he went up to Christ Church, Oxford, with a scholarship in biology; he switched to English by his second year. Friends he met at Oxford include Cecil Day-Lewis, Louis MacNeice, and Stephen Spender; these four were commonly though misleadingly identified in the 1930s as the "Auden Group" for their shared (but not identical) left-wing views. Auden left Oxford in 1928 with a third-class degree.  Auden was reintroduced to Christopher Isherwood in 1925 by his fellow student A. S. T. Fisher. For the next few years Auden sent poems to Isherwood for comments and criticism; the two maintained a sexual friendship in intervals between their relations with others. In 1935-39 they collaborated on three plays and a travel book.  From his Oxford years onward, Auden's friends uniformly described him as funny, extravagant, sympathetic, generous, and, partly by his own choice, lonely. In groups he was often dogmatic and overbearing in a comic way; in more private settings he was diffident and shy except when certain of his welcome. He was punctual in his habits, and obsessive about meeting deadlines, while choosing to live amidst physical disorder.  Auden published about four hundred poems, including seven long poems (two of them book-length). His poetry was encyclopaedic in scope and method, ranging in style from obscure twentieth-century modernism to the lucid traditional forms such as ballads and limericks, from doggerel through haiku and villanelles to a "Christmas Oratorio" and a baroque eclogue in Anglo-Saxon meters. The tone and content of his poems ranged from pop-song cliches to complex philosophical meditations, from the corns on his toes to atoms and stars, from contemporary crises to the evolution of society.  He also wrote more than four hundred essays and reviews about literature, history, politics, music, religion, and many other subjects. He collaborated on plays with Christopher Isherwood and on opera libretti with Chester Kallman, and worked with a group of artists and filmmakers on documentary films in the 1930s and with the New York Pro Musica early music group in the 1950s and 1960s. About collaboration he wrote in 1964: "collaboration has brought me greater erotic joy . . . than any sexual relations I have had."  Auden controversially rewrote or discarded some of his most famous poems when he prepared his later collected editions. He wrote that he rejected poems that he found "boring" or "dishonest" in the sense that they expressed views he had never held but had used only because he felt they would be rhetorically effective. His rejected poems include "Spain" and "September 1, 1939". His literary executor, Edward Mendelson, argues in his introduction to Selected Poems that Auden's practice reflected his sense of the persuasive power of poetry and his reluctance to misuse it. (Selected Poems includes some poems that Auden rejected and early texts of poems that he revised.)
Question: What is a popular work that he did during this time period. Whats the answer?
He collaborated on plays with Christopher Isherwood and on opera libretti with Chester Kallman,