Perseus and Andromeda (Leighton) daughters of Poseidon, the god of the sea. When the nymphs became aware of her claims, they protested to their father, who retaliated by calling up a sea monster called Cetus to patrol and wreak havoc along the coastline of Ethiopia placing Cassiope's kingdom at risk. In response the Queen, together with her husband Cepheus, decided to sacrifice her daughter, Princess Andromeda, to the monster. Andromeda was chained to a rock at the edge of the sea as an offering to the monster. Perseus was travelling back home on his winged horse, Pegasus, after battling with Medusa. He rescued Andromeda
Andromeda (constellation) daughter to Cetus. She was chained to a rock by the sea but was saved by the hero Perseus, who in one version of the story used the head of Medusa to turn the monster into stone; in another version, by the Roman poet Ovid in his Metamorphoses, Perseus slew the monster with his diamond sword. Perseus and Andromeda then married; the myth recounts that the couple had nine children together – seven sons and two daughters – and founded Mycenae and its Persideae dynasty. After Andromeda's death Athena placed her in the sky as a constellation, to honor her.