She was a monster, one of the Gorgon Sisters; the daughter of Phorkys and Keto; the grandchild of Gaea (Earth) and Oceanus (Ocean). She had the face of a woman but had hair consisting of snakes.
Sister of Sthenno and Euryale; she was the mortal of the three sisters. Originally she was a golden-haired maiden who was a priestess of the Goddess of Wisdom, Athena, who in turn had Medusa have a life devoted to celibacy, however, Medusa fell in love with Poseidon and later on married him. However, by doing this, she had betrayed Athena by not following her vows of maidenhood. Because of this, Athena was angered at Medusa and cursed her to instead have a greenish tinge to her skin, blood-shot eyes and her hair to become that of venomous snakes, causing whoever that looked into her eyes to turn to stone; after turning, it could not be reversed.