Orestes was performed in the 50th anniversary year of Aeschylus’s tragic trilogy the Oresteia, which is based on the same body of myths as Euripides’s Orestes. The Oresteia is the one surviving trilogy from antiquity. It includes the plays Agamemnon, The Libation Bearers, and The Eumenides. The first depicts Agamemnon’s fatal return home; he arrives with his “war prize” Cassandra in tow, and Clytemnestra murders both. In The Libation Bearers, Orestes returns home, having been instructed by Apollo to avenge his father by killing his mother. Orestes has trouble executing the act but Pylades encourages him, reminding him of Apollo’s command. The play ends with the Furies hunting Orestes down to punish him. The Eumenides finds him fleeing to Athens with Apollo and Hermes’s help. There, Athena sets up a trial by jury with 12 Athenian citizens. When the jury’s verdict is tied, Athena casts the deciding vote, finding Orestes innocent. The Furies become enraged, but Athena assuages their anger by promising that they will be offered a place of honor in Athens. They accept and are renamed Eumenides, meaning “kindly ones.”

When Aeschylus produced his Oresteia, Athens was at a high point. The general and politician Pericles was instituting policies that moved democracy forward in the city across all classes.