Perseus was a hero of Greek mythology. Perseus slew the Gorgon Medusa. With snakes for hair, Medusa was so hideous that anyone who set eyes on her would be turned to stone. Perseus avoided this fate by looking only at her reflection in his shield. He cut off Medusa's head and put it in a bag.

As Perseus returned home he found Andromeda.the daughter of Cepheus and Cassiopeia. tied to a rock in sacrifice to the sea monster Cetus. He fell in love with Andromeda and rescued her from the sea monster.

In the heavens, the constellation Perseus can be found next to Andromeda and nearby Casseopeia and Cepheus. The variable star Algol forms one of the eyes of Medusa's head, as Perseus holds it in his hand. This star, which has been called the demon star, is a well known variable star. This star changes brightness in a regular pattern over a period of about 2.9 days.