America: A Prophecy is a political poem which describes, in a blend of allegory, myth, and historical fact, the American War of Independence and the birth of American freedom.
The poem is not prophecy in the sense of foretelling but in the classical Biblical sense of a visionary seeing into the ideal, the true. Thus Blake sees the American rebellion as a manifestation of an eternal and idealised struggle for freedom against injustice and oppression.
England's ruler, George III, is depicted as "Albion's wrathful Prince" with "a dragon form clashing his scales". His opponent, Orc, is the physical embodiment of liberation which, at this particular moment in history, America demands.