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
Perseus Then, accused by Acrisius of lying about having slain Medusa, Perseus proves himself by showing Acrisius the Gorgon's head, thus fulfilling the prophecy. Having killed Acrisius, Perseus, who was next in line for the throne, gave the kingdom to Megapenthes ("great mourning") son of Proetus and took over Megapenthes' kingdom of Tiryns. The story is related in Pausanias, which gives as motivation for the swap that Perseus was ashamed to become king of Argos by inflicting death. In any case, early Greek literature reiterates that manslaughter, even involuntary, requires the exile of the slaughterer, expiation and ritual purification. The exchange