Some interesting facts about Cassiopeia are that she was the wife of Cepheus, the King of Ethiopia. Together, they were the parents of Andromeda, a girl known for her beauty. Cassiopeia was also a beautiful woman, but possessed of such vanity that she bragged that she was more beautiful than the Nereids. These sea nymphs were not only beautiful, but also the daughters of Nereus, a god of the sea.
When the Nereids heard about Cassiopeia's boast, they complained to Poseidon, the chief sea god. He sent a sea monster to destroy Cepheus' land.
In the wake of the devastation, Cepheus went to an oracle to find out how to mollify Poseidon. The oracle told him that he had to chain Andromeda to a rock and let the sea monster devour her. Cepheus allowed Andromeda to be chained, but fortunately the hero Perseus rescued her.
But this near disaster for her family didn't stop the gods from placing Cassiopeia in the sky as a constellation. She is presented as seated on a throne. Her husband, daughter, Perseus, his steed Pegasus and the sea monster Cetus are also constellations.
Though Cassiopeia became a constellation, she was placed in a position where she is upside down much of the time.