In Greek mythology, Medusa ("cunning queen"), was the only mortal of the three Gorgon sisters. The Gorgons were one of three triads of ancient earth deities, consisting of the three nubile Hesperides, these three dangerous "queens", and the three crones or Graeae: triple triplets of the aspects of the Triple Goddess herself.
The gorgons were vicious female monsters with brass hands, sharp fangs and hair of living, venomous serpents, which identified them as earth creatures. Medusa's cheeks puffed out, and her tongue lolled between her fangs like the bloodthirsty chthonic goddess whom she represented. She was literally petrifying to look upon: every creature who saw her was turned to a stone of the earth.
She was said to be a daughter of Phorcys and Ceto, a mortal woman whom Athena changed into a Gorgon as punishment for desecrating her temple by sleeping with Poseidon there. When Athena came upon Medusa and Poseidon (also an arch-rival of Athena's since he vied for dominance over Athens, Athena offering the olive tree, Poseidon, the horse), she turned Medusa's beautiful hair into snakey tendrils and banished her to the far ends of the earth beyond the Hyperborean lands where she remained with her sisters.