Warren began teaching at Boston University's College of Practical Arts and Letters in 1926. In 1930 he left Boston to study for a year in London on a fellowship founded by the American Council of Learned Societies. He worked part-time at the British Museum and made progress on the works he later published as "Richard Crashaw: A Study in the Baroque Sensibility" and "Alexander Pope as Critic and Humanist". Warren made the acquaintances of T. S. Eliot and Evelyn Underhill before returning to Boston University in the fall of 1931, where he became a Professor of English before his departure in 1939.