Andromeda Chained to the Rock by the Nereids
In Greek mythology, Andromeda was the daughter of Cepheus and Cassiopeia, king and queen of the North African kingdom of Aethiopia (the Upper Nile region).
Her mother Cassiopeia boasted that her daughter was more beautiful than the Nereids, the nymph-daughters of the sea god Nereusand often seen accompanying Poseidon. To punish the queen for her arrogance, Poseidon, brother to Zeus and god of the sea, sent a sea monster named Cetus to ravage the coast of Aethiopia including the kingdom of the vain queen. The desperate king consulted the Oracle of Apollo, who announced that no respite would be found until the king sacrificed his daughter, Andromeda, to the monster. Stripped naked, she was chained to a rock on the coast.
Perseus was returning from having slain the Gorgon Medusa. After he happened upon the chained Andromeda, he approached Cetus while invisible (for he was wearing Hades's helm), and killed the sea monster. He set Andromeda free, and married her in spite of her having been previously promised to her uncle Phineus. At the wedding a quarrel took place between the rivals and Phineus was turned to stone by the sight of the Gorgon's head. More at: Wikipedia
Andromeda Chained to the Rocks
by Rembrandt in 1631,
and is now in the Mauritshuis, in The Hagu
Andromeda's parents thank Perseus for freeing her;
La Délivrance d'Andromède
by Pierre Mignard (1679)