Seeing the face of a Gorgon turns the viewer to stone. Hesiod makes the number of Gorgons three—Stheno (the mighty), Euryale (the far-springer) and Medusa (the queen), and makes them the daughters of the sea-god Phorcys and of Keto. Their home is on the farthest side of the western ocean; according to later authorities, in Libya. The Attic tradition, reproduced in Euripides regarded the Gorgon as a monster, produced by Gaia to aid her sons the Titans against the gods and slain by Athena. Of the three Gorgons, only Medusa is mortal. According to Ovid, Medusa alone had serpents in her hair, and this was due to Athena cursing her. Medusa had copulated with Poseidon, who was aroused by the golden colour of Medusa's hair, in a temple of Athena. Athena therefore changed the enticing golden locks into serpents. Aeschylus says that the three Gorgons had only one tooth and one eye among them, which they had to swap among themselves.