Blake was engaged on the epic poem called Jerusalem, the Emanation of the Giant Albion from 1804 to 1820. Although the form we have of the poem may appear to be final – in a sense in which Vala, or, The Four Zoas never achieved finality – one may nevertheless question in what sense such a poem can ever be 'complete'. This is because Blake here, as often elsewhere, appears to be engaged on several different enterprises at once, and we may discern four levels to the poem.
At the first level, he is concerned to construct a myth within which the central players are the 'giant forms' known as Albion and Jerusalem. We may figure the relations between these 'characters' in various different ways. Jerusalem, for …
Punter, David. "Jerusalem: the Emanation of the Great Albion". The Literary Encyclopedia. First published 17 July 2001
[http://www.litencyc.com/php/sworks.php?rec=true&UID=4309, accessed 26 April 2017.]