Thetis bore one son, Achilles, whom she tried unsuccessfully to make immortal. In one version of the story, she anointed the infant's body with ambrosia and then placed it upon a fire in order to burn away the mortal parts; when she was interrupted by the child's horrified father, she deserted their household in a rage. In a later version, she dipped the child in the river Styx holding him by the heel; all the parts that the river touched became invulnerable, but the heel remained dry. Achilles was later killed in the Trojan war.