Long ago in Ethiopia, Andromeda was the daughter of Cassiopeia and Cepheus. Unfortunately her mother was extremely vain and thought herself to be more beautiful than the daughters of Nereus, a god of the sea. So the wrath of the god Poseidon fell on Cassiopeia. To punish her, Andromeda was chained to a rock off the coast as a sacrifice for a sea monster. Yet she escaped from death, being saved by Perseus. For rescuing her, he demanded Andromeda as his wife, which the parents gladly accepted.

The famous Andromneda Galaxy (M31) and its companion galaxies are located at the Northern end of the constellation.