His brilliant diplomatic career began in 1892, and he eventually served as ambassador to Japan (1921-27) and the U.S. (1927-33). At the same time he pursued a literary career, expressing in poetry and drama his conception of the grand design of creation. He reached his largest audience through plays such as Break of Noon (1906), The Hostage (1911), Tidings Brought to Mary (1912), and his masterpiece, The Satin Slipper (1929); recurring themes in these works are human and divine love and the search for salvation. He wrote the librettos for Darius Milhaud's opera Christopher Columbus (1930) and Arthur Honegger's oratorio Joan of Arc (1938). His best-known poetic work is the confessional Five Great Odes (1910)