Cassiopeia, in Greek mythology, an Ethiopian queen, wife of Cepheus and mother of Andromeda. Cassiopeia was so proud of her daughter's beauty that she boasted that it surpassed that of the Nereids or sea-nymphs. The incensed nymphs begged Poseidon for vengeance. In response to their prayer a deluge laid waste the dominions of Cepheus, and a fearful monster appeared on the coast to still further ravage the country. Cepheus, inquiring of the oracle, learned that only the sacrifice of the beautiful Andromeda would appease the wrath of the ocean dwellers. Andromeda, therefore, was chained to a rock on the sea-coast to be devoured by the monster. While awaiting her horrible fate, she was seen by Perseus, flying homeward with Hermes' winged shoes, and carrying Medusa's head. Perseus dropped to earth, learned the troubles of Andromeda, slew the monster, and married the maiden. For a time the sea nymphs ceased to harass Cassiopeia. At her death, however, she was given a place among the stars, which angered them anew. Their only recourse was to cause her position in the heavens to be such that in revolving about the pole star, she should hang head downward half the time. This, perhaps, to teach her humility. The constellation Cassiopeia is known as the Lady in her Chair. In charts of the constellations she is represented as a draped figure reclining in a chair and holding up both arms. There are fifty-five stars in the constellation, five of which, forming a capital W, are of the third magnitude. A new star appeared in the constellation in 1572. For a time it shone as brightly as Venus, then disappeared.
That starred Ethiope Queen that strove
To set her beauty's praise above
The sea-nymphs, and their powers offended.
—Milton.
