Medusa was the youngest and most beautiful of the three
    daughters of the sea Titans Porcys and Ceto. She was blessed with untold beauty
    and had long flowing hair that  fell gently down from her
    head. Medusa was the only mortal of the three sisters, and all  were very wise serving as priestesses under the goddess of
    wisdom and war Athena.
    The god Poseidon longed for beautiful Medusa, and in a
    moment of uncontrolled passion he raped Medusa  in Athena's own
    temple.  The three sisters than became angry and hated all men do to
    Poseidon's action.
    Athena soon grew disgusted with  the three sisters new found wickedness, and
    the defiling sexual act that was committed  in her temple.  Athena transformed the three girls into hideous beasts, with
    wings and numerous snakes for hair. These beasts became known as the Gorgons
    and were so horrid to behold that whosoever looked at them would  instantly
    turn to stone. 
    
Medusa the Gorgon
    As time went on Medusa and her sisters grew continually more wicked
    and took untold pleasure in torturing their victims. Their cruelty
    was than brought to an end by the Greek hero Perseus who with the help of
    the gods slew  Medusa. 
    The goddess Athena provided Perseus with a silver shield,
    the god Hermes
    winged sandals, and the god Hades a helmet which would make the wearer invisible.
    Wearing Hades helmet Perseus became invisible and approached
    the sleeping Medusa. He slew her by looking at her image through a
    reflection on Athena's shield, but never looked upon her with his own eyes
    knowing full well that this would turn him to stone. Chopping off her head
    he placed it into a bag to present it later to the goddess Athena.
    But as soon as he slue the Gorgon Medusa her sisters woke up in
    rage and raced to capture and kill Perseus, but with the help of the winged
    sandals that Hermes had given him, and the invisible helmet of Hades he managed to
    evade an escape the angered sisters.
    
Perseus
    with Medusa's head
    From Medusa's dead body sprang forth the elegant winged
    horse Pegasus and the giant winged horse Chrysaor the result of the union of Medusa and
    Poseidon.
    Perseus than presented Medusa's head to the goddess Athena, who
    placed Medusa's head into the center of her shield the Aegis, which she than
    wore
    over her breastplate.