John Keats (pronounced /ˈkiːts/; 31 October 1795 – 23 February 1821) was an English poet, who became one of the key figures of the Romantic movement. During his very short life his work received constant critical attacks from periodicals of the day, but his posthumous influence on poets such as Alfred Tennyson and Wilfred Owen would be immense. Keats's poetry was characterised by elaborate word choice and sensual imagery, notably in a series of odes that were his masterpieces, and which remain among the most popular poems in English literature. Keats's letters, which expound on his aesthetic theory of "negative capability",^[1] are among the most celebrated by any writer.