"Henry Paul, who informs the reader that Buchanan's Historia Scotica, and Hector Boece's Historia Scotorum were used as source material for Shakespeare's Macbeth, may not be aware that copies of both these books containing Bacon's inked annotations exist, and that these annotations show Bacon's special interest in the Macbeth theme. On a page of Buchanan containing the story of Macbeth, Bacon has written "Macbethi, Macbetho, and Macbethus Tyrannus, and Bancho rigiae caedis." Many of the words in the text are underlined. And in a copy of Boece dated 1575, Bacon has written the genealogy of the Scottish Kings descended from Banquo "to, and including James V, comprising seven kings." And in his Natural History, Bacon shows the same interest in strange parts of animals that Shakespeare must have had to write the witches' scenes."
- from this review of The Royal Play of Macbeth by Henry N Paul