Who is not a modern poet?

Among the poets:

-- William Butler Yeats, (born June 13, 1865, Sandymount, Dublin, Ireland—died January 28, 1939, Roquebrune-Cap-Martin, France), Irish poet, dramatist, and prose writer, one of the greatest English-language poets of the 20th century. He received the Nobel Prize for Literature in 1923.--- 

W. H. Auden, in full Wystan Hugh Auden, (born February 21, 1907, York, Yorkshire, England—died September 29, 1973, Vienna, Austria), English-born poet and man of letters who achieved early fame in the 1930s as a hero of the left during the Great Depression.-

-- John Keats, (born October 31, 1795, London, England—died February 23, 1821, Rome, Papal States [Italy]), English Romantic lyric poet who devoted his short life to the perfection of a poetry marked by vivid imagery, great sensuous appeal, and an attempt to express a philosophy through classical legend.--- 

T.S. Eliot, in full Thomas Stearns Eliot, (born September 26, 1888, St. Louis, Missouri, U.S.—died January 4, 1965, London, England), American-English poet, playwright, literary critic, and editor, a leader of the Modernist movement in poetry in such works as The Waste Land (1922) and Four Quartets (1943). Eliot exercised a strong influence on Anglo-American culture from the 1920s until late in the century.

--- So, William Butler Yeats, W. H. Auden and T.S. Eliot are Modern poet and literary figures.

-- On the other hand, John Keats is a English Romantic Period's poet.

john keats is a poet of the Romantic age.