scholar, civil servant, and art collector who influenced the development of contemporary British art by patronizing unestablished artists. He was also an editor, translator, and biographer who was well-known in British literary circles of the early 20th century.

Marsh entered the civil service in 1896; beginning in 1905 he served for more than 20 years as private secretary to Winston Churchill (Churchill, Winston). By 1904 Marsh was an important private collector of Old Master paintings; he later turned to collecting the work of contemporary British artists, helping to popularize painters such as Duncan Grant (Grant, Duncan), Stanley Spencer (Spencer, Sir Stanley), Mark Gertler, and John and Paul Nash (Nash, Paul).

Marsh edited The Collected Poems of Rupert Brooke (1918) and Georgian Poetry (1912–22), a five-volume anthology of modern poetry. He translated the French poet Jean de La Fontaine (La Fontaine, Jean de)'s Fables (1931) and The Odes of Horace (1941), and he wrote a series of reminiscences entitled A Number of People (1939). Marsh was knighted upon his retirement in 1937.