 Echidna's family tree varies by author.The oldest genealogy relating to Echidna, Hesiod's "Theogony" (c. 8th – 7th century BC), is unclear on several points.According to Hesiod, Echidna was born to a "she" who was probably meant by Hesiod to be the sea goddess Ceto, making Echidna's likely father the sea god Phorcys; however the "she" might instead refer to the Oceanid Callirhoe, which would make Medusa's offspring Chrysaor the father of Echidna.