Medea was the daughter of Aetes and Idyia. Another variations of her myth, say that her mother was Hekate or Neaira or Eurulete or Ipsea.
She was taught by Hekate the art of using herbs and poison making. She was liberating many strangers in her town, Iolkos, that's why her father put her in prison. She escaped and she found asylum in the temple of Helios, which was by the sea. She continued to help strangers.
Mythology
When argonautai came in Iolkos (east of the Black Sea), she offered to help them. She cooperated with them using her brilliant mind. She hide herbs inside the statue of Artemis, she entered the town as a guided holy person by Artemis. She declared that Artemis was flying all over the world and she found her place in Iolkos. So the crowd was very happy and full of enthousiasm. She motivated Pelia's daughters to slaughter their father,with the promise that she will resurect him as young person. She slaughtered a ram and she boiled all the dead parts with herbs in a cauldron. All together took torches and they were praying to Selene. When the Argonautai saw this light-sign they knew that Pelias was dead, so they invaded the town.
Media and Jason, the leader of Argonautai, moved to Korinth and they lived happily for ten years. Jason married another woman, Glauke and he abandoned Medea. Medea was very angry. She reminded him his vows... King Kreon announces to Medea that she and her sons are not welcome in the city. They had to leave immediately. But Medea was not any ordinary woman to let that happen easily. She was searching for revenge. So, she took a cloak and she gave it to Glauke as a gift for marriage. The cloak was enchanted, so Glauke's skin was burn. Kreon who hugged her also died. The fire was continuing burning the palace. In this crazy situation, Medea was killing her children except Thettalos and she left for Athens in a flying chariot, driven by snakes. Another variation says that the Korintheans slaughtered her children.
With Aigeus she gave birth to Medos. Theseas, the king of Athens, banished them. They moved to Phoenike of Asia.
After her death, people of Kolchis honored her. Marce of Italy honored her as a Goddess of healing.
History
Medea was vary efficient of using herbs for healing, for making paints, for making poisons. In the lost work of Sophocles, rootcutters, she was presented as skilled as Calypso and Kirke. Diogenes Laertios writes that Medea had cured Hercule's madness when he met him in Thebes. She was also the inventor of sauna or pyriaterion as it is in hellenic. That's why there is the myth with the cauldron... Sauna makes good for the skin, that's why she said that people will become younger. She probably didn't killed her children, but the Korintheans did. They also gave five talanta to Euripides in order to write the tragedy of Medea, by their variation.
Hekate and Medea
In the book Argonautica we read the Hekate was invoked by Medea to her magick. In her garden we find many herbs, all associated with Hekate. In Argonautica of Apollodorus we find that Medea taught Jason how to invoke Hekate and how to makie offereing to Her and we also read about the associations of the serpents and oak with Her. Sophocles writes in his lost work rootcutters how Medea was working with herbs, which were cut by her using a bronze boleen! In the work of Seneca, Medea associated with necromancy. In Eyripides work, Medea, she says that her Goddess is Hekate, she respects Her more than other Gods, as She is helping her, Her throne exists in her house too. Medea also admits that Hekate is the Goddess who helps Witches in their operations.
Image: Jason and Medea by John William Waterhouse
 
It amazes me how so many traditions follow these ancient protocols and roles,