When Orestes was a baby, his father Agamemnon left home to lead the Greek armies in the Trojan War, leaving his wife, Clytemnestra, in charge of Mycenae. The campaign took a long time to prepare, and the war itself lasted 10 years, so Orestes was in his early teens by the time his father returned.
The Trojan War had not even begun when Agamemnon provoked the anger of the gods. While the Greeks were still gathering their fleet at the port of Aulis in readiness to transport their army to Troy, Agamemnon boasted that he was a better hunter than the goddess Artemis. To punish Agamemnon’s hubris (pride), Artemis angrily stilled the winds so that the Greek ships could not set sail. A soothsayer told Agamemnon that the winds would return only if he sacrificed his daughter Iphigeneia to the offended goddess. With great sadness and reluctance, Agamemnon did his penance and had Iphigeneia killed on Artemis’s altar. Clytemnestra never forgave her husband for allowing their daughter to be sacrificed and sought ways to avenge her death. Before long she joined forces with her cousin, Aegisthus, who hated Agamemnon as a consequence of an earlier conflict between their fathers, Thyestes and Atreus, respectively.
Clytemnestra was at first reluctant to conspire with Aegisthus, but they later became lovers and she yielded to her desire for revenge and power. With Agamemnon away at Troy, the pair began to rule Mycenae as king and queen and made plans to kill Agamemnon when he returned. They forced Clytemnestra’s surviving daughters to accept the new regime, but one of them, Electra, sent Orestes for safety to Agamemnon’s ally Strophius, king of Phocis. That saved Orestes, for Aegisthus would not have allowed the heir to the throne to live.
When Agamemnon returned home to Mycenae with a mistress, the Trojan princess Cassandra, Clytemnestra and Aegisthus murdered the pair of them. They then ruled Mycenae for seven years. Orestes remained with Strophius, whose son Pylades became his close friend. When they reached manhood, they resolved to reclaim Orestes’ birthright and avenge Agamemnon’s death. They consulted the oracle of Apollo at Delphi, and Orestes was told to slay the killers of his father.
The friends then proceeded to Mycenae and entered the city in secret. They made contact with Electra, who in one version had been compelled to marry a farmer so that her children would be ineligible to inherit the kingdom. Electra idolized her dead father and hated her mother and stepfather. She was therefore willing to help her brother. Together, the three young people managed to kill Aegisthus and Clytemnestra.
Although Orestes had acted with Apollo’s approval, he was still guilty of matricide (killing one’s mother), so he was vulnerable to attack by the Erinyes (Furies), goddesses of vengeance who tormented all criminals.
These hideous demons pursued Orestes across Greece until he at last came to Athens. There a group of citizens assembled to hear his case, which Apollo .
Defended since he originally supported Orestes’ cause. The prosecution was presented according to some accounts by the Erinyes, in others by Clytemnestra’s father,
Tyndareos, or by Erigone, daughter of Aegisthus and Clytemnestra. The jury was divided, so Athena, the city’s patron goddess, cast the deciding vote. Since Athena herself was born directly from Zeus and had no mother, she sympathized with Agamemnon as a father
Right: The painting on this Greek vase, dated about 500 BCE, shows Orestes killing Aegisthus.
Figure. She ruled that Orestes’ revenge was justifiable homicide. After she delivered her verdict the Erinyes agreed to become patrons of Athens, and were renamed the Eumenides (“Kindly Ones”).