I was looking for something else on McCabe’s flickr stream and came across this image that really changed how I saw this type (but see my earlier post my earlier post for evolution of this line of thought).
Notice how the slave’s face is turned out to look at the audience. Often the frontal face in Greek and Roman art is reserved for the monstrous, often the feminine monstrous. Also his hair is longer than the Roman’s and that may be a torque around his neck…
Also notice the footwear on the Roman and the lack there of on the slave:
just memorializing this exceptionally good specimen from in trade: Numismatica Ars Classica NAC AG, Auction 106, lot 387, 9/05/2018