Long ago in Ethiopia, Cassiopeia was the wife of Cepheus and the mother of Andromeda. Because she thought herself more beautiful than the daughters of Nereus, a god of the sea, she incurred the wrath of the god Poseidon. To punish her, her daughter Andromeda was chained to a rock off the coast as a sacrifice for a sea monster. Andromeda was saved from death by Perseus. (Publius Ovidius Naso: Metamophoses, IV). To learn humility, Cassiopeia was banished to the sky, hanging half of the time head downward. For Northern Hemisphere observers, Cassiopeia circles the North pole, and is visible every night of the year.