The coin images of the Roman denarius remained unchanged over a long time: The obverse bore the head of the goddess Roma, while the reverse showed the Dioscuri Castor and Pollux riding into battle.
Around 200 BC, however, the motifs on the reverse began to vary. The so-called bigati appeared, a denarius depicting the moon goddess Luna driving a biga. This coin is such a bigatus; Luna is recognizable by the crescent over her head.