Jason, Greek mythological hero. Jason laid claim to the kingdom of Iolkos, which his uncle, Pelias, had seized from Jason's father, Aeson. Pelias agreed to return the kingdom if Jason brought him the magical Golden Fleece, held by King Aeetes of Colchis. Jason assembled a force, the Argonauts, who set sail in the Argo to seek the fleece. After many adventures, they recovered the fleece, with the aid of Aeetes's daughter, Medea, who fell in love with Jason. She accompanied him back to Greece and became his queen. But when Jason tried to divorce Medea, she destroyed Creusa, his bride-to-be, as well as Creusa's father, and (in some versions of the story) her own children. The gods then caused Jason to wander aimlessly until his death.