Queen Cassiopeia is a figure from Greek mythology, known for her beauty and vanity. She was the wife of King Cepheus and the mother of Princess Andromeda. Cassiopeia boasted that she and her daughter were more beautiful than the sea nymphs, the Nereids, which angered the sea god Poseidon. To punish her, Poseidon sent a sea monster, Cetus, to ravage their kingdom. To appease the god, Cassiopeia and Cepheus were forced to sacrifice Andromeda. However, the hero Perseus saved her, leading to a series of events that ultimately resulted in Cassiopeia's placement in the night sky as a constellation.