The Gorgoneion is the name given to the head of the Gorgon Medusa. According to Greek mythology, Medusa was originally a hideous and terrifying monster-woman with snakes in her hair, who could turn anyone who looked at her to stone. This monster was killed by Perseus who gave the Gorgon’s head to Athena-Minerva in gratitude for her help. Minerva then placed it on her shield or aegis (breastplate) where it had an apotropaic function (to ward off enemies, who were terrified by the sight of it).
The Gorgon Medusa was often presented as she is on the coin shown opposite (a denarius from the Republican Period): her face is broad, her eyes very large, and in her hair we can see the sinuous bodies of the snakes. The image of the Gorgon was extremely popular in Antiquity.