Agamemnon is the first of the three plays within the Oresteia trilogy. It tells the story of the homecoming of Agamemnon, King of Argos, from the Trojan War. Waiting at home for him is his wife, Clytemnestra, who has been planning his murder as revenge for the sacrifice of their daughter, Iphigenia. Furthermore, in the ten years of Agamemnon's absence, Clytemnestra has entered into an adulterous relationship with Aegisthus, Agamemnon's cousin and the scion of a dispossessed branch of the family, who is determined to regain the throne he believes should rightfully belong to him.