Closeup images (click images or here to enlarge) from two Billon (silver/bronze alloy) Antoniniani of Aurelian (Augustus, 270-275). As described in the blog post here the coins depict captives of Parthian or other Persian origin, indicated by the Phrygian Cap.
Left: From a Silvered Antoninianus of Aurelian, 274 AD, depicting Sol standing with a bound captive at his foot.
Right: From a Billon Antoninianus of Aurelian, 274 AD, depicting Sol standing above two bound captives.