In Greek mythology and ancient Greek art, a gorgoneion was Medusa’s head used as a protective emblem.
The gorgoneion was a frontal image of a Gorgon’s face, especially Medusa’s, placed on shields, armor, pottery, temples, coins, and other objects. Its frightening appearance was thought to ward off evil or repel enemies. The image could include staring eyes, protruding features, and snakes around the head.
After Perseus killed Medusa, he gave or presented her head to Athena in the best-known tradition. Athena then placed it on her aegis, turning the dangerous head into a powerful divine symbol. The emblem therefore combines the mythic event with a long-lived artistic motif.
A gorgoneion is not the same thing as the aegis itself. The aegis is the protective garment or shield-like object associated with Athena and Zeus; the gorgoneion is the Gorgon-head image attached to or displayed on such objects.