Jerusalem, or "And did those feet in ancient time" is a short poem by English poet William Blake. Parry set these famous words to music in his great unison song Anthem in 1916. The poem was inspired by the apocryphal story that young Jesus actually traveled to England, a legend in the Book of Revelation describing a New Jerusalem. The song was also taken up by the Suffragettes in 1917. The song was changed to Jerusalem as a metaphor, that when Britain was made perfect, there would be heaven on earth. The work is considered to be England's most popular patriotic song.
The music has been taken up by the Church of England and is frequently sung as a recessional hymn on St. George's Day.
Most recently the song was used in the wedding of Prince William and Kate Middleton to great applause.