This painting illustrates a story in the Metamorphoses, an epic poem by the ancient Roman writer Ovid. Battus watched Mercury hiding stolen cattle but promised to keep the god’s secret. However, Mercury – god of commerce as well as thieves – was suspicious. He returned in disguise to bribe the old man to reveal the herd’s whereabouts, which he duly did. For this indiscretion, Mercury turned Battus into a rock. The stone statue here refers to this imminent punishment.