The Chained Lady or The Princess
The Hubris of Cassiopeia
Andromeda was the daughter of King Cepheus and Queen Cassiopeia of Ethiopia. Her mother Queen Cassiopeia was an exceedingly vain lady who dared to boast that she was more beautiful than even the Nereids, a group of fifty sea nymphs of exquisite beauty. The Nereids were so affronted at the presumption of the vain queen that they begged Poseidon to punish her.
The Punishment by Poseidon
In response to the pleas of the Nereids, Poseidon sent the sea monster Cetus to ravage Ethiopia. When King Cepheus asked the Oracle at Ammon what he must do to appease the anger of the god, he was told that he must sacrifice his beautiful virgin daughter to the sea monster. So he chained Andromeda to a rock on the Mediterranean shore at Jaffa (the present-day city of Tel Aviv) to await the approach of the monster.
How Her Life Was Saved
The story has a happy ending though, because the life of Andromeda was saved by the hero Perseus who slew the monster and claimed the hand of Andromeda in marriage.