The three Gorgon sisters — Medusa, Stheno, and Euryale — were children of Phorcys and Ceto, chthonic monsters from an archaic world.
In the majority of the versions of the story, while Medusa was pregnant by Poseidon, she was beheaded by the hero Perseus, who was sent to fetch her head by King Polydectes of Seriphus. With help from Athena and Hermes, who supplied him with winged sandals, Hades' cap of invisibility, a sword, and a mirrored shield, he accomplished his quest. The hero slew Medusa by looking at her reflection in the mirror instead of directly at her to prevent being turned into stone. When the hero severed Medusa's head, from her neck two offspring sprang forth: the winged horse Pegasus and the giant Chrysaor who later became the hero wielding the golden sword.

Perseus

Head of Medusa, Architectural element, Museum of Diocletian Therms, Roma

Caravaggio, Head of Medusa

Antonio Canova, Perseus

The reflection of the head of Medusa on the shield of Perseus