Jason, the son of King Aeson of Iolcus, was brought up by the kind, wise centaur Chiron, to whom his mother fled for help when her husband's throne was usurped by his half-brother, Pelias. As he grew, Jason was determined to regain the throne. The cunning Pelias agreed his claim, with the proviso that Jason first brought back the Golden Fleece from Colchis, since he believed that (a) it was highly unlikely that Jason would be able to accomplish such a feat and would probably perish in the attempt and (b) that should he miraculously manage to return with the Fleece, he would at the same time bring back the soul of his cousin, Phrixus, who some years earlier had been saved by the ram and taken to Colchis (see Legend of Aries). Phrixus had never been truly content in exile and an oracle had issued dire warnings as to what would befall his homeland should his soul never be brought back there to rest.

Accordingly, Jason had a magnificent ship constructed, named the Argo. The goddess Athene brought a board cut from Zeus's sacred oak and placed it in the prow. It was a huge vessel, with fifty oars manned by fifty great heroes of Greece, including Heracles, Orpheus, Castor and Pollux. The Argonauts set sail, but as they approached the Bosphorous they saw the ancient seer Phineus being attacked by Harpies (animals with the body of a bird and the face of a witch). Earlier, Phineus had unwittingly made known some of Zeus's many affairs, and the angry god sent these Harpies to contaminate anything he tried to eat. The Argonauts saved the old man and, in gratitude, he advised them on the best way to navigate the Clashing Rocks which guarded the entrance to the Black Sea. First a dove was released, and when this negotiated the gap successfully with only its tail feathers clipped, Jason urged on his men to their utmost effort and the Argo sailed safely through.

When Jason finally arrived in Colchis, King Aeetes would not immediately give him the Golden Fleece, but insisted that he first undertook several almost impossible tasks, including yoking wild bulls and ploughing a field with them, and then sowing dragons' teeth from which sprang armed warriors all eager to kill him. Fortunately, he was assisted by Medea, the daughter of Aeetes, who gave him a magic potion. This enabled him to successfully complete all his assigned tasks, and to steal the Golden Fleece and return with it to his homeland.

See Legend of Aries