Andromeda was a daughter of Cepheus and Cassiopeia. Her vain mother boasted of being more beautiful that the Nereids, insulting the various deities of the Sea. Poseidon send The Kraken to ravage the coast of Ethiopia.
The only chance for Cepheus to appease the God was to sacrifice his virgin daughter Andromeda. Perseus, a young hero returning from slaying Medusa, offered to face the monster in exchange for the hand of Andromeda.
Perseus and Andromeda later rose to the throne of Mycenae. Their children included Alcaeus, Autochthoe, Electryon, Gorgophone, Heleus, Mestor, Perses, and Sthenelus. Their descendants included many heroes, most notably Heracles.