It's Claudius II with a reverse of VIRTVS AVG Mars advancing right, holding trophy and spear; struck AD 269 - 270 at the Milan mint.
Here's a short history of Claudius from my notebook. Antoninianus of Claudius II, Obverse: IMP C CLAVDIVS AVG “Emperor caesar Claudius augustus.” Reverse: FIDES AVG (reverse lettering is blundered, “FEDIS”.) “Fidelity to the emperor.” Mercury holding a purse and caduceus, officina mark “Z” below. RIC 207, Sear 11333 · Marcus Aurelius Valerius Claudius along with Aureolus were responsible for the assassination of the Gallienus. Claudius had risen up through the ranks of military, as many high ranking Romans had done. · Despite his less than admirable rise to power, the Senate, which had not regarded Gallienus highly, confirmed his claim to the throne. He soon proved his worthiness to the throne. · He defeated an invasion by the Alamanni, weakened the Gallic Empire by invading its Spanish and Gaul territories and inflicted a massive defeat on the Goths at the Battle of Naissus. The Goths had been plundering the Balkans for some time. In recognition of his great victory over the Goths, Claudius had the appellation “Gothicus” added to his name. · Many of the defeated Goths were recruited into the Roman Army. This proved to be a disaster because they brought with them another round of plague. · The plague claimed the life of Claudius Gothicus thus cutting short his reign.
