The severed head of Medusa stares out from the convex face of a two-sided relief. Its psychological realism, simultaneously beautiful and hideous, reveals the conflicting yet symbiotic emotions of attraction and repulsion. This combination expresses the power of ancient Greek apotropaic objects, charms that warded off evil. Since the sight of Medusa's face–transformed by the goddess Athena into a monster with snakes for hair–had turned men into stone, it became a traditional apotropaic symbol. Athena affixed the actual Medusa's monstrous head to her shield, and human warriors followed suit.
The sculptor Vincenzo Gemito derived his composition from the famous antique cameo, the Tazza Farnese, but transformed it into an entirely new kind of sculptural object. He revived Renaissance techniques of lost-wax casting to make the relief. Although he concentrated on the face of the two-sided, glistening metallic relief, he textured the back with snakeskin.