Prized hide of a winged ram in Greek mythology…

Prized hide of a winged ram in Greek mythology, kept in the land of Colchis on the Black Sea. It hung from an oak tree in a sacred grove, guarded by a dragon that never slept. King Pelias sent his nephew Jason to fetch it. Sailing aboard the ship Argo with heroes such as Heracles and Orpheus, Jason won it with help from the sorceress Medea, daughter of King Aeetes.

The answer in 12 letters