This song contains Blake’s Prologue, Intended for a Dramatic Piece of King Edward the Fourth.
Although I own the one or other record of Loreena McKennitt, I am sorry to say that I owe this find to the Wikipedia Page Blake in Popular Culture.
You can listen to it here on YouTube, uploaded by Loreena McKennitt.
Text taken from:
Blake, William. “Prologue, Intended for a Dramatic Piece of King Edward the Fourth.” In The Complete Poetry & Prose of William Blake. ed. by David V. Erdmann. The Blake Archive. http://erdman.blakearchive.org/#439