• Shakespeare, who never could think up a plot by himself, found this one [Macbeth] in Holinshed's Chronicles, changing it just enough so that no one would recognize the source. He didn't count on the resourcefulness of modern scholars, who have to discover things like this to become associate professors.

    Richard Armour, William Shakespeare (1957). “Twisted Tales from Shakespeare, in which Shakespeare's Best-known Plays are Presented in a New Light: The Old Light Having Blown a Fuse; Together with Introductions, Questions, Appendices, and Other Critical Apparatus Intended to Contribute to a Clearer Misunderstanding of the Subject”, new American Library of Canada