E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A generic name for a black footman, as Abigail used to be of a ladys maid. Moll or Molly is a cook; Betty, a housemaid; Sambo, a black buttons; etc. One of Hoods jokes for a list of library books was, Pompeii; or, Memoirs of a Black Footman, by Sir W. Gill. (Sir W. Gell wrote a book on Pompeii.) Pompey is also a common name for a dog.