The Witch of Colchis by Rosie Hewlett

For readers of Costanza Casati and Circe comes an evocative tale of love, murder, and magic following one of the most powerful and maligned women in Greek myth. Meet Medea like you've never known her before - a woman with improbable skill and the softest heart, held back by men who could never dream to deserve her.
A disgraced daughter. A fearsome witch.
A woman more myth than mortal.
Medea, princess of Colchis, longs for a different life. Since childhood, she has been shunned from her family, tormented by her people, and treated with shame. All because of a unique and dangerous talent: witchcraft.
But when a dashing young hero, Jason, arrives to claim the famed Golden Fleece, Medea sees her opportunity for escape. Her offer to help Jason sets in motion a journey that will test every ounce of strength, magic, and loyalty she has. A journey that will see her battle monsters, dethrone kings, and confront a love more brutal than any before.
A journey that will ultimately end in betrayal, bloodshed, and a dark power impossible to forget.