The canvas is part of a series of paintings dedicated to the famous mythological hero. Together with the other three exhibited next to it, it once adorned the halls of Palazzo Cattaneo Adorno (today Via Garibaldi), a home where there were also the other monumental representations of the Metamorphoses , acquired at the same time by the Galleria Nazionale della Liguria.

Hercules is in this case depicted as he passes the second of the twelve tests he was subjected to to atone for the guilt of having exterminated his own family. The sea monster about to succumb to his feet is the Hydra of Lerna, endowed with numerous heads capable of regrowth. The skin that the hero wears is instead the proof of overcoming the first effort, or the fight against the Nemean lion.