Poseidon's punishment: Cassiopeia as aconstellation sitting in the heavens tied to a chair. Hyginus,Poeticon Astronomicon. "U.S. Naval Observatory Library"
Her origins are obscure.Nonnus calls her anymph,[2] while according toStephanus she was called Iope, the daughter ofAeolus, from whom the town of Joppa (Jaffa) derived its name.[3]
The king of EthiopiaCepheus and the queen Cassiopeia thankPerseus for freeing their daughter Andromeda,La Délivrance d'Andromède (1679)Pierre Mignard,Louvre
Cassiopeia boasted that she (or her daughterAndromeda), was more beautiful than all theNereids, the nymph-daughters of the sea godNereus. This brought the wrath ofPoseidon, ruling god of the sea, upon the kingdom of Aethiopia.[4]
Accounts differ as to whether Poseidon decided to flood the whole country[5] or direct thesea monsterCetus to destroy it. In either case, trying to save their kingdom, Cepheus and Cassiopeia consulted a wise oracle, who told them that the only way to appease the sea gods was to sacrifice their daughter.
Accordingly, Andromeda was chained to a rock at the sea's edge and left to be killed by the sea monster.Perseus arrived and instead killed Cetus, saved Andromeda and married her.[5]
Poseidon thought Cassiopeia should not escape punishment, so he placed her in the heavens chained to a throne in a position that referenced Andromeda's ordeal. The constellation resembles the chair that originally represented aninstrument of torture. Cassiopeia is not always represented tied to the chair in torment; in some later drawings she holds a mirror, symbol of her vanity, while in others she holds apalm frond.[6][7][8]
The constellationCassiopeia, near to thepole star, can be seen from latitudes north of 35°N during the whole year. The constellation is also visible in countries north of theTropic of Capricorn, in late spring.
According to the1922 regnal list of Ethiopia, Cassiopeia ruled Ethiopia as part of the Agdazyan dynasty and reigned for 19 years from 1890 to 1871 BC, with dates following theEthiopian calendar.[9]
Stephanus of Byzantium,Stephani Byzantii Ethnicorum quae supersunt, edited by August Meineike (1790-1870), published 1849. A few entries from this important ancient handbook of place names have been translated by Brady Kiesling.Online version at the Topos Text Project.
Tripp, Edward,Crowell's Handbook of Classical Mythology, Thomas Y. Crowell Co; First edition (June 1970).ISBN069022608X.