Not to be confused with Jason Grace.
Jason was a late ancient Greek mythological 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) and Polymede (the daughter of Autolycus), and was once married to the sorceress Medea. He was also a legacy of Hermes on his mother's side and Prometheus on his father's side.
The son of King Aeson of Iolcus and his wife Amphinome, 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 while in the process losing his sandal. In an attempt to preserve 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's 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, Pelias refused to give Jason the throne until his death depsite getting the fleece. So 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. As a result, 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 Cornith. 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 Cornith 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.
- Jason Grace was named after him by his father, Jupiter, to placate his wife, Juno's, anger and to appease her, despite the disapproval of his mother. Apparently, Juno/Hera liked the name and Jason was her favorite mortal, and hero who was not a demigod or son by her husband, even though he lost her favor after breaking his vow to Medea.
- While Jason is seen as a human hero, he was actually a legacy of Hermes through his grandfather Autolycus. Interestingly, his father was a descendant of Deucalion, a son of Prometheus. This would make Jason a descendant of both Hermes and Prometheus.
- He was the cousin of Odysseus. Both their mothers were daughters of Autolycus.
- Hercules met Theseus at presumably the same time as Jason met Medea. But Theseus met Medea years ago in Athens, and she was supposed to have fled to Athens after killing her and Jason's kids. This is currently an unsolved error.