Coachboy

[je_nny]

'John Miller's Coachboy' (painted over an early 18th C portrait of John Hanby, aged 25) by British (English) School
Collection: National Trust
This imaginary portrait of a dimly-remembered black coachboy who worked for John Mellor (1665-1733), an owner of Erddig, was painted over an early eighteenth-century portrait of an otherwise unknown John Hanby, aged 25 (who was probably a white man).

Насколько я понимаю, "Coachboy" - это парень, который ездил на козлах коляски и трубил в трубу - типа гудка автомобильного. Как-то так.