The poem was inspired by the apocryphal story that a young Jesus, accompanied by his uncle Joseph of Arimathea, travelled to England and visited Glastonbury. This legend is linked to an idea in the Book of Revelation (3:12 and 21:2) describing a Second Coming wherein Jesus establishes a new Jerusalem. The Christian Church in general, and the English Church in particular, used Jerusalem as a metaphor for Heaven, a place of universal love and peace. The poem therefore implies that the visit of Jesus briefly created heaven in England and this is contrasted with the 'dark Satanic mills'. (The hymn 'Jerusalem the Golden with milk and honey blessed... I know not oh I know not what joys await me there....' uses Jerusalem for the same metaphor).
Some of Blake's biographers have concluded that he believed in the legend, but he may not have intended such a literal interpretation because he asks questions rather than making statements. Instead it can be thought as saying that there may, or may not, have been a divine visit when there was briefly heaven in England, but that was then; now we should accept the challenge to create such a country once more.
The term "dark Satanic mills", which entered the English language from this poem, is sometimes interpreted as referring to the early industrial revolution and its destruction of nature. This view has been linked to the fate of the Albion Flour Mills, which was the first major factory in London, built in 1769 by Matthew Boulton and James Watt. It was powered by Watt's steam engines, and produced 6,000 bushels of flour a week. The factory could have driven independent traditional millers out of business, but it was destroyed, perhaps deliberately, by fire in 1791. London's independent millers celebrated with placards reading, "Success to the mills of ALBION but no Albion Mills." Opponents referred to the factory as satanic, and accused its owners of adulterating flour and using cheap imports at the expense of British producers. An illustration of the fire published at the time shows a devil squatting on the building. The mills were a short distance from Blake's home.
Another common interpretation is that the dark satanic mills refer to the gloomy churches of the established Church of England, full of mechanistic ceremony but devoid of spiritualism, which in the late 18th century sought to maintain the established political order, unlike the emergent non-conformist free church movements of Methodism, Congregationalism and the Baptists who held that through Jesus Christ all men were equal under God. Blake's views, expressed through his metaphysical writings and paintings, were attacked by an Anglican church he held was a force crushing the spiritual growth of the nation. Some hold that his call to build a new Jerusalem reflected calls for a new egalitarianism in English society. The hymn specifically asks the question that could it be here, where Jesus walked, that a new society be built, a call adopted by the Methodist and Christian Socialist movement and subsequently by the Labour Party.
An alternative theory is that Blake refers to Stonehenge; an illustration of it and other megaliths is featured in his work, Milton. However, he did not see ancient Britain as satanic, but rather saw the Druids and their supposed temple, Stonehenge, as precursors of Christianity. Satan's "mills" are referred to repeatedly in the main poem, and are first described in words which suggest neither industrialism nor ancient megaliths, but rather something more abstract: "the starry Mills of Satan/ Are built beneath the earth and waters of the Mundane Shell...To Mortals thy Mills seem everything, and the Harrow of Shaddai / A scheme of human conduct invisible and incomprehensible".
The poem, which was little known during the century which followed its writing, was included in a patriotic anthology of verse published in 1916, a time when morale had begun to decline due to the high number of casualties in the First World War and the perception that there was no end in sight.
Under these circumstances, it seemed to many to define what England was fighting for. Therefore, Robert Bridges, the Poet Laureate asked Parry to put it to music at a Fight for Right campaign meeting in London's Queen's Hall. The aims of this organisation were "to brace the spirit of the nation that the people of Great Britain, knowing that they are fighting for the best interests of humanity, may refuse any temptation, however insidious, to conclude a premature peace, and may accept with cheerfulness all the sacrifices necessary to bring the war to a satisfactory conclusion". Bridges asked Parry to supply the verse with "suitable, simple music that an audience could take up and join in". Originally Parry intended the first verse to be sung by a solo female voice, but this is rare nowadays. The most famous version was orchestrated by Sir Edward Elgar in 1922 for a large orchestra at the Leeds Festival. Upon hearing the orchestral version for the first time, King George V said that he preferred "Jerusalem" over "God Save the King", the National Anthem.
England does not have an official anthem and so the British National Anthem "God Save the Queen" is used for national occasions, for example before English international football matches. Since Jerusalem is considered to be England's most popular patriotic song, it has been used as an alternative national anthem and there have been calls to give it official status. However critics of the song have said that its reference to a foreign city, its non-secular basis and the negative answers to each of its four questions make it unsuitable.
The poem's idealistic theme or subtext accounts for its popularity across the philosophical spectrum. It was used as a campaign slogan by the Labour Party in the 1945 general election; Clement Attlee said they would build "a new Jerusalem. The song is also the unofficial anthem of the British Women's Institute, and historically was used by the National Union of Suffrage Societies. It has been sung at conferences of the British Conservative Party, at the Glee Club of the British Liberal Assembly and by British Liberal Democrats. It is frequently sung as an office or recessional hymn in English cathedrals, churches and chapels on St George's Day. The hymn is also sung in some churches on Jerusalem Sunday, a day set aside to celebrate the holy city, in Anglican Churches throughout the world and even in some Episcopal Churches in the U.S.
However some vicars in the Church of England, according to the BBC TV programme "Jerusalem: An Anthem for England", have said that the song is not technically a hymn, as it is not a prayer to God (which hymns always are). Consequently, it is not sung in some churches in England..
Parry's tune is so well liked that the song is not only sung in many schools, especially public schools in the UK (it was used as the title music for the BBC's 1979 series 'Public School' at Radley College) , but also at several private schools in New England and Canada. Some attempts have also been made to increase its use elsewhere with other words. The established Church of Scotland debated altering the words of the hymn to read "Albion" instead of England to make it more locally relevant. The tune has been set to several texts in the United States, where the traditional lyrics would have little relevance, including "O Love of God, how strong and true", which was performed in an arrangement by Michael McCarthy at Ronald Reagan's funeral at Washington National Cathedral in 2004. In some hymnals the tune is used with Carl P. Daw Jr.'s text "O Day of Peace That Dimly Shines" (based on Isaiah 11:1-9).