The origin of his sobriquet is uncertain: it could be due to his swarthy complexion, but possibly also to excessive facial hair, a port-wine birthmark, or perhaps a punning reference to his friend Blewitt.
The origin of his nickname is unclear: it could be due to his dark complexion, but possibly also to excessive facial hair, a birthmark on his face, or perhaps a humorous reference to his friend Blewitt.