In Greek mythology, Andromeda (, "Androméda" or Ἀνδρομέδη, "Andromédē") is an Aethiopian princess, the daughter of King Cepheus and his wife Cassiopeia. When Cassiopeia boasted that her daughter was more beautiful than the Nereids, this angered the sea god Poseidon, who sent the sea monster Ceto to ravage the land as punishment. Desperate, King Cepheus consulted the Oracle of Delphi, who stated that Andromeda must be offered as a sacrifice to the sea monster; Andromeda was then chained to a rock by the shore. When the hero Perseus saw Andromeda (having flown over after beheading Medusa), he killed the sea monster and saved Andromeda. They were soon married, with Perseus going on to found the city of Mycenae. By Perseus, she is the mother of Perses, Alcaeus, Heleus, Mestor, Sthenelus and Electryon as well as two daughters Autochthe and Gorgophone. Andromeda is also the great-grandmother of Herakles. 