Whilst I think the origins of blacking up for morris are still a bit obscure, there is certainly a weight of evidence that suggests it comes from the minstrels.

Which raises the question, where did the conventional wisdom that it is simply about disguise come from? That has been the accepted notion for as long as I can remember. Is it denial? Wishful thinking? Was there any historical evidence to support it, or is it one of those things, like morris being a pagan fertility rite, that emerged from someone's fevered imagination?