Let Gryll be Gryll, and keep his hoggish mind. Don't attempt to wash a blackamoor white; the leeopard will never change his spots. Gryll is from the Greek gru (the grunting of a hog). When Sir Guyon disenchanted the forms in the Bower of Bliss some were exceedingly angry, and one in particular, named Gryll, who had been metamorphosed by Acrasia into a hog, abused him most roundly. “Come,” says the palmer to Sir Guyon,
Let Gryll be Gryll, and have his hoggish mind. But let us hence depart while weather serves. and wind.
Spenser Faërie Queene, book ii. 12