Jason was a late ancient Greek hero, famous as the leader of the Argonauts and their quest for the Golden Fleece. He was the son of Aeson, the rightful king of Iolcus, with Polymede, the daughter of Autolycus. He was married to the sorceress Medea.
The mortal son of King Aeson of Iolcus, Jason's father was driven from his throne by his half-brother Pelias. Due to a prophecy that Jason would one day kill him, Pelias attempted to have Jason killed, but his mother saved him by sending him to Chiron to be raised. An oracle later informed Pelias that a man with one sandal would overthrow him.
Years later Jason returned to claim his throne. On the journey he helped the goddess Hera in disguise earning her favor. Trying to save his throne Pelias demanded Jason take an impossible quest to obtain the Golden Fleece. To accomplish this Jason assembled a team of heroes that became known as the Argonauts, due to their ship being called the Argo. After many adventures they came to the island of Colchis where the Fleece was kept
King Aeetes of Colchis attempted to stop Jason from taking the Fleece by demanding he complete several impossible tasks. Hera intervened and persuaded Aphrodite to cause Aeetes' daughter Medea to fall in love with Jason and aid him with her magic. With her help, Jason and his men obtained the Fleece and fled, but killed Medea's brother Apsyrtus to delay Aeetes. It was Medea's idea to cut her brother's body up into pieces so that her father would have to stop and retrieve them to give Apsyrtus a proper burial.
Upon their return. Medea tricked Pelias' daughter into killing him by thinking they were restoring his youth by cutting him up and throwing his body into a fountain. Jason and Medea were forced into exile by Pelias' son and fled to Cornith. At some point the two married and had children. Jason eventually betrayed Medea when he abandoned her to marry the princess of Corinth. According to some sources when confronted with his treachery Jason claimed he truly owed the gods for his success and Medea nothing. The stories vary, but Medea unleashed a horrible revenge by burning the princess of Corinth and her father to death with a poisoned dress. Some stories state she even killed her own children either to protect them from revenge or as part of her own vengeance. Other stories state her children were killed by an angry mob when she was driven from the city.
Jason with the aid of Achilles' father Peleus was able to reclaim the throne of Iolcus, and was succeeded by his son. However, his previous treachery regarding Medea caused him to lose the favor of the gods, including Hera. He was driven away and spent his last years as a lonely beggar reflecting on past glories. When sitting under the rotting Argo one day, he died when a piece of it fell off and hit him on the head.