The Second Punic War (218-201 BC) was devastating for Rome. It caused fundamental changes in the Roman state and its society. All because of a young general named Hannibal, who had led his army through Spain and Gaul, across the Alps and into Northern Italy. Most of the fighting took place on the Italian peninsula, and with it came destruction, looting, and killing.
The Romans suffered one defeat after another. They were forced to incessantly arrange new troops and fleets, and to produce new arms. The Roman finances were extremely strained. This was reflected in the coinage reform from around 213/212 BC. For the first time Rome introduced a silver currency based on a large, valuable silver coin. This was the denarius, the coin worth 10 asses. The traditional bronze coin, the as, became small change.
The new silver coin bore on its obverse Dea Roma, the personification of the Roman state. On the reverse, Castor and Pollux hurried to help the Romans in battle.