Perseus (constellation) may be derived from the Babylonian Old Man (MUL.SHU.GI) constellation, then associated with East in the MUL.APINan astronomical compilation dating to around 1000 BCE. In Greek mythology, Perseus was the son of Danaë, who was sent by King Polydectes to bring the head of Medusa the Gorgon — whose visage caused all who gazed upon her to turn to stone. Perseus slew Medusa in her sleep, and Pegasus and Chrysaor appeared from her body. Perseus continued to the realm of Cepheus whose daughter Andromeda was to be sacrificed to Cetus the sea monster. Perseus rescued Andromeda from the monster by
Medusa who was turned into stone by the head. Then Perseus gave the Gorgon's head to Athena, who placed it on her shield, the Aegis. Some classical references refer to three Gorgons; Harrison considered that the tripling of Medusa into a trio of sisters was a secondary feature in the myth: A number of early classics scholars interpreted the myth of the Medusa as a quasi-historical – "based on or reconstructed from an event, custom, style, etc., in the past", or "sublimated" memory of an actual invasion. According to Joseph Campbell: In 1940, Sigmund Freud's "Das Medusenhaupt (Medusa's Head)" was published