In Greek mythology, who was Queen Cassiopeia's daughter, who she claimed was more beautiful than the Nereids?

In Greek mythology, Andromeda is the daughter of Cepheus and Cassiopeia, king and queen of ancient Ethiopia. Her mother Cassiopeia foolishly boasts that she is more beautiful than the Nereids, a display of hubris by a human that is unacceptable to the gods. To punish the queen for her arrogance, Poseidon floods the Ethiopian coast and sends a sea monster named Cetus to ravage the kingdom's inhabitants. In desperation, King Cepheus consults the oracle of Ammon, who announces that no respite can be found until the king sacrifices his daughter, Andromeda, to the monster. She is thus chained to a rock by the sea to await her death.

Perseus is flying near the coast of Ethiopia on his winged sandals, having slain the Gorgon Medusa and carrying her severed head, which instantly turns to stone any who looks at it. Upon seeing Andromeda bound to the rock, Perseus falls in love with her, and he secures Cepheus' promise of her hand in marriage if he can save her. Perseus kills the monster with the magical sword he had used against Medusa, saving Andromeda. Perseus marries Andromeda and takes her to Greece to reign as his queen.