From Colchis, the land of the magical Golden Fleece, Medea is the daughter of King Aeetes and granddaughter of Helios, the sun god. She met and fell in love with Jason when he arrived in Colchis on a quest for the Golden Fleece. Medea has magical powers and used them to help Jason in his quest. The pair ended up in Corinth, where they began raising their children. But now Jason has left Medea to marry the princess of Corinth. The play opens with Medea raging at Jason's betrayal. She plots and executes her revenge on Jason, even denying her parental feelings toward her children.
Jason was born a prince of Iolcus, but when his uncle Pelias usurped the throne from Jason's father, Jason was sent to the centaur Chiron to be trained as a Greek hero. When he was old enough to seek his birthright—the throne of Iolcus—Jason acquired a ship called the Argos and manned it with a crew called the Argonauts. Jason and the Argonauts set sail to take up King Pelias's challenge to bring the Golden Fleece to Iolcus. Supported by Medea's magic, Jason used his hero training to complete a series of difficult tasks set by King Aeetes of Colchis, Medea's father. In the play Jason's betrayal of Medea stings all the more because of how she has loved and helped him throughout his exploits. He claims to want to help his family by leaving Medea, but she doesn't see that as a valid excuse.