Daughter of King Cephus and Queen Cassiopeia of Ethiopia, who had angered Poseidon by claiming she was more beautiful than the Nereids (the sea-nymphs). The sea-god sent a sea monster to torment Ethopia, and an oracle then said that if Andromache was sacrificed, the monster would leave. The princess was chained to a rock by the sea, but was rescued by Perseus who turned the monster into stone after showing it the head of Medusa.
Perseus went to king Cephesus to ask for Andromedas hand, and the king gladlyagreed. His brother Phineus was angered though, because he had been promised Andromeda. Phineus and his followers tried to take the princess, but Perseus turned them all into stone using Medusa's head.Andromeda eventually became Perseus wife and queen of Tiryns. The couple founded Midia and Mycenae, and their children were Alcaios, Electryon and Sthenelos. Perseus, Andromeda, Cassiopeia and also Cephus were later turned into star constellations.