From Art to Artifact:  Making Sense of Roman Coins

The Dioscuri appear on horseback in the first issue of Roman denarii (Crawford 53/2), which were minted in 211 BCE. They continue to appear on denarii of the same type in an unbroken series for the next seventy years.

Though this type first appeared on the Bruttium coin, the Dioscuri on horseback had special meaning to the Romans. In Roman tradition, the Dioscuri appeared on horseback during the battle of Lake Regillus in the early fifth century BCE and won the day for the Romans; and subsequently a temple was built to them in the Forum. Henceforth they were worshipped as the gods of the cavalry.

This coin and the subsequent repetition of the type show the continuing resonance of the Dioscuri as symbols. It is significant that they are represented on horseback, in their military function as gods of the cavalry.