Probus - Rome - RIC 160 Bust Type C
Obv:– IMP C M AVR PROBVS P F AVG, Radiate, draped and cuirassed bust right, seen from the front
Rev:– ADVENTVS PROBI AVG, Emperor riding left, right hand raised, left holding sceptre; at foot, captive
Minted in Rome (//RA) Emission 2 Officina 1. A.D. 277
Reference:– RIC 160 Bust Type C.
According to Dr. Sylviane Estiot this looks like it is only the second example of this type known, the other being in the BM (same reverse die). (Published by Estiot and Gysen in Revue Numismatique 2006)