Jason was the son of Aeson King of Iolkos of Thessaly, who was forced to flee with his son on Mount Pelion in order to save his brother Pelias seized him by fraud to the throne.

The Aeson handed his son to the custody and care of the Centaur Chiron, who was brought up many heroes and high schools.

When Jason grew up and learned that the throne of Iolkos was his, took his weapons and went into the country, to seek justice from the. But passing a small river, the Anavros the water swept one of his sandals and thus presented to Pelias' monosandalos.

Pelias, who by some oracle knew that must be stored in a monosandalo for fear of losing his throne

"... By monosandalo parafylaxou Siddha Panos from the haunts of the gkremera Joined Iolkou will make one day xefanti earth and heard of a foreigner or fellow countrymen ..."

Pindar IV, Pythia

Jason sent in a faraway country, AIA, to bring him the Golden Fleece in the hope that the new fee would turn ever from that dangerous adventure.

"... May be issues as you want, but look at the weather
longer has to move about the years old but you
the flower of youth protanochto kymosalefei
rage and you can cut of chthonic gods.
The soul of our land to bring Frixos commands
the palaces of Aeetes going and skin
vathymallo of the ram, which from the back of the Sea
the wicked and the stepmother of sagites in escaped.
Thamasto my dream and sued mantalogi
kastaliotiko gyrepsa if you need to look beyond
I slow down without any karavostoli
to rig for Dante. Eager shut t 'feat
and give you the royal olakero your Amun.
In axesalefto witness caw orkodeti Zeus
and our two grandfathered "

Pindar, Pythian IV f. 183-197

Jason then accepted with great pleasure the dangerous mission of his uncle, hoping that he would do a great achievement, and glorify, like so many other heroes.
Invite friends, Hercules, Theseus, Castor, the Pollux, Peleus, Telamon in the musician Orpheus, and the prophets Mopso Idmon the giant Polyphemus, Asclepius, son of Phrixus a slow and many others and with the help of Argos built a beautiful boat called the Argo. The heroes called the Argonauts, and their journey was named Argonaut expedition.