In classical antiquity the image of the head of Medusa was consider to have the power to avert evil, and was used as a protective emblem, known as the Gorgoneion. Similar images have been used since Neolithic times to represent aspects of the Mother Goddess associated with "dynamic life energy"
In Greek mythology, Medusa was a monster, a Gorgon, generally described as a winged human female with living venomous snakes in place of hair. Those who gazed upon her face would turn to stone.
Medusa was beheaded by the hero Perseus, who thereafter used her head, which retained its ability to turn onlookers to stone, as a weapon until he gave it to the goddess Athena to place on her shield.