Confusingly, the lyric to the hymn Jerusalem, the single work for which Blake is arguably best known, is not connected to this poem. It is in fact the preface from another of his "prophetic books", Milton: a Poem.
The poem, which was produced between 1804 and 1820, consists of 100 etched and illustrated plates. This would be Blake's longest single work. The illustrated plates were made using Blake's self-devised technique of "illuminated printing". This required each copy to be individually coloured and produced plate by plate. Blake was not averse to changing the text of some plates between printings or changing the colouring, as a result of which no two original copies of the poem are the same. The sole extant colour edition of this work is in the collection of the Yale Center for British Art in New Haven, Connecticut.
Because it includes a cast of billions, Jerusalem can seem confusing. The poem does not have a linear plot. Characters morph in and out of each other. A character can be a person and a place. Jerusalem, the Emanation of Albion, is a woman and a city. Albion, "the Universal Humanity," is a man and a land (Britain). He contains twelve sons who co-inhere with the twelve tribes of Israel, as well as Four Zoas. Every Zoa (embodying a life principle) has an Emanation (a feminine figure through which the human can become divine). The Zoas and Emanations include:
Jerusalem's first chapter tells the story of Albion's fall into Selfhood. Its overture sets the scene for Los's journey into Albion's interior and humanity's transfiguration in forgiveness of sins. In the first scene Albion banishes Jerusalem and Jesus, blighting nature, culture, and his internal life. Then Los contends with his Spectre, forcing him to work for Albion's restoration. Jerusalem mourns, animating shadowy Vala as Los builds Golgonooza, a city that can open into Edenic Eternity. Urizenic rationality assaults Jerusalem and enshrouds the life of the mind. Los battles against this, mapping Britain onto Israel, but his shadowy Spectre infects him with wrath and shame, stalking Albion's daughters and empowering Albion's warrior sons who banish Jerusalem. Vala tries to seduce Jerusalem. Albion curses them both, and finds himself enmeshed in Vala's deadly veil. He refuses divine forgiveness.
Blake's Jews co-inhere with bellicose British Druids. In this chapter Los and a host of angelic Eternals attempt to rescue Albion. Los's Spectre and Emanation appear as refugees, fleeing from Albion to tell their version of his fall. Los journeys into Albion's interior where bloodthirsty Vala is worshipped. Then Los sensually constricts Reuben (Albion's son) in an attempt to control his lusts as Jesus imaginatively creates states through which humanity can find forgiveness. Angelmorphic Eternals (cathedral cities) seek to help Albion, but they too get blighted by Selfhood. Los rouses them, but Albion chooses to remain trapped. Vala tramples Jerusalem but wise Erin (Ireland) separates the poem's heroine from Albion in whose body she is infected with bellicose Moral Law.
Blake's Deists create more violence than the Christianity they critique. When the chapter begins Albion's rational Moral Law infects Los, Albion falls yet again, and Vala's bellicose erotics encompass humanity. Urizen builds what he thinks is a redemptive Druid temple and Jerusalem works in Satanic mills where, infected by industrial chaos and Albion's morality, she can barely perceive Jesus and divine forgiveness. Vala melds with the rational beast, spreading war throughout the world, and her daughters enjoy human sacrifice. The peace of "heavenly Canaan" still hovers above Ulro's chaos, but Los fallibly builds Golgonooza which becomes the structure of "Religion Hid in War." The harlot-dragon reigns.
Now universal humanity awakens to forgiveness. Jerusalem finally melds love with wrath, confronting shadowy Vala whose daughters weave death. As Los sings, Jerusalem appears tri-locational, emanating angelmorphic and descending as a city and a woman. Sexual contentions obstruct Los' work and Vala thrusts her wrath cup upon Jerusalem who is devoured by the dragon to rise again. Los keeps building, freeing himself from gender disputes. Time ends. The Breath Divine breathes. Albion awakens, and sees that Los is Christ and Christ is Los. He throws himself into Los's fires which become fountains of living water. Fragmented Zoas reunite in wars of love, in the Song of Jerusalem. All living things become a great Divine Body.