Cassiopeia
Cepheus was a king. His wife was Cassiopeia. The two had a daughter named Andromeda. Cassiopeia claimed she was more beautiful than a Nereid, which was a sea nymph. The Nereids were offended and told Poseidon, who was the sea god. Poseidon sent a huge serpent to harm Cassiopeia. The serpent destroyed the land, and King Cepheus turned to an oracle for help. The only way to stop the monster was to offer up Andromeda, the daughter. Andromeda was offered as a sacrifice while chained to a rock. Before she was killed, Perseus saved her. Next, Cassiopeia was sent to the stars to remind everyone to not be vain.