The Oresteia is a trilogy of Greek tragedies written by Aeschylus concerning the end of the curse on the House of Atreus. The name derives from the character Orestes, who sets out to avenge his father's murder. The only extant example of an ancient Greek theater trilogy, the Oresteia won first prize at the Dionysia festival in 458 BC. When originally performed, it was accompanied by Proteus, a satyr play that would have followed the trilogy. Proteus has not survived, however.

In all likelihood the term "Oresteia" originally referred to all four plays; today it generally designates only the surviving trilogy. Many consider the Oresteia to be Aeschylus' finest work. Principal themes of the trilogy include the contrast between revenge and justice, as well as the transition from personal vendetta to organized litigation. The Libation Bearers is the second play of the Oresteia. It deals with the reunion of Agamemnon's children, Electra and Orestes, and their revenge. Orestes kills Clytemnestra to avenge the death of Agamemnon, Orestes' father. Summary by Wikipedia.