Some posts on Soubise
From the Yale Center for British Art (the whole exhibition for the symposium is really good):
Dueling Image http://interactive.britishart.yale.edu/slavery-and-portraiture/282/the-d-------of-----playing-at-foils-with-her-favorite-lap-dog-mungo-after-expending-near-%C2%A310000-to-make-him-a----------
Marconi http://interactive.britishart.yale.edu/slavery-and-portraiture/278/a-mungo-macaroni