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 Twa Sisters brought to her father's hall and plays before the entire court, telling of her sister's crime. The song also mentions her brother named Hugh, and her beloved William, and gives a name to the older sister, Anne. An early Alfred Lord Tennyson poem, "The Sisters", also bears a resemblance to the ballad: a sister scorned in love who murders the lover of her sister, and possibly the sister too, out of jealousy. The Twa Sisters "The Two Sisters" is a Northumbrian murder ballad that recounts the tale of a girl drowned by her sister. It is first known to have