"And did those feet in ancient time" is a poem by William Blake from the preface to his epic Milton: A Poem in Two Books, one of a collection of writings known as the Prophetic Books. The date of 1804 on the title page is probably when the plates were begun, but the poem was printed c. 1808. Today it is best known as the hymn "Jerusalem", with music written by Sir Hubert Parry in 1916. The famous orchestration was written by Sir Edward Elgar. It is not to be confused with another poem, much longer and larger in scope and also by Blake, called Jerusalem The Emanation of the Giant Albion.

William Blake was an English poet, painter, and printmaker. Largely unrecognised during his life, Blake is now considered a seminal figure in the history of the poetry and visual art of the Romantic Age. What he called his "prophetic works" were said by 20th-century critic Northrop Frye to form "what is in proportion to its merits the least read body of poetry in the English language". While he lived in London his entire life, except for three years spent in Felpham, he produced a diverse and symbolically rich collection of works, which embraced the imagination as "the body of God", or "human existence itself".