Medea was daughter of King Aeeta of Colchis and the niece of Circe. She was a magician-sorceress like her aunt. According to legend Medea developed quite a reputation, and not all good. She was to cure Aegeus of his sterility. Being under Medea's influence she had him invited an strange visitor, Theseus whom Medea had guessed was Aegeus' son, in Athens to a banquet with the intention of poisoning him. Theseus accepted to come, but when appearing with the sword and sandals once hidden under a rock Aegeus immediately recognized him as his son. Aegeus quickly exiled Medea and Theseus was recognized by his own people.
There is tale that Medea imposed a test on Theseus, or got his father to, before her poison attempt. The challenge was for Theseus to fight a Marathonian bull, a fierce animal that was devastating the countryside. Perhaps the Cretan bull brought back by Hercules. Theseus overpowered the beast and offered it in sacrifice to Apollo.
Medea is known for her violent passion for Jason. He had told her father King Aeetes of his mission to fetch the Golden Fleece. The king agreed to give it to him but set certain conditions which Jason could have never fulfilled if Medea had not aided him. The conditions were that Jason must yoke a pair of fire-eating bulls with brazen feet, presents from Hephaestus. Then, with them, he had to plough a field and sow it with dragon teeth from the dragon of Thebes. Before rendering her help Medea made Jason promise to marry her. She gave Jason balm with which to anoint himself before facing the bulls and taught him how to handle them. Thus Jason successfully managed the bulls and ploughed the field. However, when he had sown the dragon teeth a group of armed men jumped out of the ploughed field. Jason quickly hid himself and threw a stone in their midst. The warriors began accusing one another of throwing the rock and fought until they killed each other.
King Aeetes did not keep his promise and even tried setting fire to the Argo. Medea by her witchcraft put the dragon asleep which guarded the Golden Fleece so Jason could take it from the sacred oak tree on which it hung. Medea then fled with Jason taking her young brother, Apsyrtus, with them. Aeetes started after the Argo and to prevent her father from overtaking them Medea chopped up her little brother into pieces and threw him in the sea. While Aeetes was busy retrieving body parts of his son the Argo escaped.
Medea is next heard of after Jason ends his exploits and Pelias refuses to hand over his kingdom to him. The sorceress then persuades Pelias' daughters to attempt to renew their father's youth by magical means, which she promised to reveal to them. But she gives them wrong instructions and they only succeed in killing their father. As a result of this murder Jason and Medea had to seek refuge in Corinth where they stayed for ten years. By now Jason had grown tired of Medea and became betrothed to Creusa, daughter of King Creon. Medea gave Creusa a nuptial gown which threw forth violent flames when she put it on and consumed the entire royal palace altogether including Creon. Afterwards Medea killed he two children she had by Jason and fled on a winged chariot.
Following this Medea led a wondering life remaining for awhile at Athens with Aegeus until he discovered that she tried tricking into poisoning Theseus, his son. After Aegeus expelled her she took refuge in Asia, in the land of Media, which took its name from her. Then she returned to her father, restored his kingdom to him, for it had meanwhile been seized by Perses, the brother of Aeetes.
Another legend is that Medea never died, being carried off into the underworld to become the wife of Achilles. A.G.H.
Grimal, Pierre, Larousse World Mythology, Secaucus, New Jersey, Chartwell Books, 1965, pp. 149, 150, 151, 152