The Gorgons, Stheno, Euryale, and Medusa, were the three daughters of Phorcys and Ceto, and were the personification of those benumbing, and, as it were, petrifying sensations, which result from sudden and extreme fear. They were frightful winged monsters, whose bodies were covered with scales; hissing, wriggling snakes clustered round their heads instead of hair; their hands were of brass; their teeth resembled the tusks of a wild boar; and their whole aspect was so appalling, that they are said to have turned into stone all who beheld them. These terrible sisters were supposed to dwell in that remote and mysterious region in the far West, beyond the sacred stream of Oceanus.
The Gorgons were the servants of Aïdes, who made use of them to terrify and overawe those shades, doomed to be kept in a constant state of unrest as a punishment for their misdeeds, whilst the Furies, on their part, scourged them with their whips and tortured them incessantly. The most celebrated of the three sisters was Medusa, who alone was mortal. She was originally a golden-haired and very beautiful maiden, who, as a priestess of Athene, was devoted to a life of celibacy; but, being wooed by Poseidon, whom she loved in return, she forgot her vows, and became united to him in marriage. For this offence she was punished by the goddess in a most terrible manner.
Each wavy lock of the beautiful hair which had so charmed her husband, was changed into a venomous snake; her once gentle, love-inspiring eyes now became blood-shot, furious orbs, which excited fear and disgust in the mind of the beholder; whilst her former roseate hue and milk-white skin assumed a loathsome greenish tinge. Seeing herself thus transformed into so repulsive an object, Medusa fled from her home, never to return.
Wandering about, abhorred, dreaded, and shunned by all the world, she now developed into a character, worthy of her outward appearance. In her despair she fled to Africa, where, as she passed restlessly from place to place, infant snakes dropped from her hair, and thus, according to the belief of the ancients, that country became the hotbed of these venomous reptiles. With the curse of Athene upon her, she turned into stone whomsoever she gazed upon, till at last, after a life of nameless misery, deliverance came to her in the shape of death, at the hands of Perseus. It is well to observe that when the Gorgons are spoken of in the singular, it is Medusa who is alluded to. Medusa was the mother of Pegasus and Chrysaor, father of the three-headed, winged giant Geryones, who was slain by Heracles.
From: Berens, E.M. The Myths and Legends of Ancient Greece and Rome. New York: Maynard, Merril, & Co., 1880. Text in the public domain.