Black Guard is a term used in the 16th century for the lowest menials of a noble house, the scullions who cleaned pots and pans. It was also used of the hangers-on of an army, camp-followers, then a rabble, vagabonds.
Black Guard
Chambers's Encyclopaedia, Volume 2: Beaugency to Cataract, p. 200
Source scan(s): p. 0211