What is the earliest deception of Medea in Greek mythology?

The earliest deception of Medea in Greek mythology occurs when she first encounters Jason, who seeks the Golden Fleece. Medea, a powerful sorceress, deceives her own family by betraying them to help Jason succeed in his quest. She uses her magical abilities to assist him, ultimately leading to her elopement with Jason and the murder of her brother, Absyrtus, as a means of covering her tracks. This act of betrayal sets the stage for the tragic events that follow in their lives.