Henchman

A groom. An attendant. A right-hand man.

"The Foster-brother, having the same Education as the young Chief, may besides that become his Hanchman. This Officer is a Sort of Secretary, and is to be ready upon all Occasions, to venture his Life in defence of his Master; and at Drinking-bouts he stands behind his Seat, at his Haunch, from whence his Title is derived, and watches the Conversation."

Edward Burt, Letters from a gentleman in the north of Scotland (1730).