Thetis was the daughter of Nereus and Doris, one of the fifty Nereids. She was destined to bear a child mightier than his father. For this reason, Zeus did not mate with her. Thetis married a mortal King Peleus. At their wedding feast, Eris, who happened to have not been invited, threw a golden apple marked ‘To the Fairest' which in turn caused the Trojan War. Thetis and Peleus, as predicted, had a son called Achilles. Thetis wanted him to be invulnerable and dipped the infant into the River Styx. All of Achilles was covered by the waters except for his heel, by which his mother held him. He was later killed by Paris when he shot Achilles in this vulnerable spot. Thetis possessed the power of shape shifting, a characteristic many gods share.
