Andromeda, the princess:

Along with Perseus, Cassiopeia, Cepheus, and Pegasus, Andromeda is involved in one of the oldest stories in history and is one of the most ancient constellations. Andromeda was an ancient princess who was saved from being sacrificed to the sea monster Cetus by the hero Perseus. Cassiopeia and Cepheus are her parents, who are forced to sacrifice their daughter as punishment for insulting the ancient gods. Within the constellation of Andromeda is located M31, the Andromeda Galaxy. M31 is a spiral galaxy similar to our own Milky Way, and is the most distant object a person can observe without the use of a telescope. The constellation is located to the east of Pegasus and just below Cassiopeia.