Medusa part of their religion. Medusa was beheaded by the hero Perseus, who thereafter used her head, which retained its ability to turn onlookers to stone, as a weapon until he gave it to the goddess Athena to place on her shield. In classical antiquity the image of the head of Medusa appeared in the evil-averting device known as the "Gorgoneion". The three Gorgon sisters—Medusa, Stheno, and Euryale—were all children of the ancient marine deities Phorcys (or "Phorkys") and his sister Ceto (or "Keto"), chthonic monsters from an archaic world. Their genealogy is shared with other sisters, the Graeae, as in
The Son of Neptune Riordan on Percy's birthday, August 18. Nine months after Percy Jackson's defense of Mount Olympus in "The Last Olympian", Percy finds himself alone and on the run from monsters in southern California without his memories. Under the initial guidance of Lupa, the wolf-goddess and protector of ancient Rome, he makes his way toward Camp Jupiter, the Roman demigod training camp and counterpart to the Greek demigods' Camp Half-Blood. Upon arriving, he is attacked by several Gorgons — Stheno and Euryale — and successfully defends a disguised goddess Juno and the camp with the help of the guards on duty. Having