Gallienus, AE antoninianus, Rome, sole reign.

IMP GALLIENVS PF AVG, radiate head right.
MARTI PACIFERO, Mars standing left, holding olive branch, 
spear and resting hand on shield

RIC V-1 Rome 236 var (obv. legend); Göbl 657 var (ditto)
Rare.

Courtesy of cngcoins.com