It was all because of Helen. The devastating Trojan War which killed more Greeks and Trojans than possible in order for Helen, taken by the Trojan, Paris, to be restored to Agamemnon’s brother, Menelaus. The Trojan War has been raging for 10 long years, and finally the Greeks, victorious but wary, are returning home. A lone sentinel waits for the return of the great general, Agamemnon to his home. The watchman laments the long wait he has had, and the dreadful events that have occurred over the past few years at home while he, loyally, waits for the return of his master. It appears that the mistress of the house, Clytemnestra, has tired of waiting for her husband’s return and has found herself a lover, Aegisthus, to take over her husband’s bed. Soon the watchman catches sight of Agamemnon’s ship in the distance. He cries out in joy of Agamemnon’s triumphant return after so many years of war.
However, Agamemnon does not return from Troy innocent of guilt. The chorus speak of how he lured his own daughter, Iphigenia to be sacrificed for the war. Agamemnon gave word that Iphigenia would be married to Achilles in Argos, however, it was all a ruse to sacrifice her to the Gods so that the Greek army could sail off to war with Troy.
Clytemnestra never forgave her husband for his ignoble act, nor for the death of their daughter.
Already unhappy of her husband’s return, Clytemnestra is soon enraged at the slave-mistress Agamemnon has dared to bring into her sight. Cassandra, the Trojan Princess, is herself afraid of her forced entrance into the Greek household, for she is clairvoyant and dreads the danger which awaits Agamemnon and herself at the hands of Clytemnestra and her lover. No one believes her visions, however, and Agamemnon walks confidently to his death.
After Clytaemnestra has killed both her husband and his new mistress, Cassandra, she claims that her act was just in revenge for her daughter’s death. She isjoined by her lover, Aegisthus, and they take over the kingdom. Nevertheless, the chorus foretell her doom at the hand of her son, Orestes, who is in exile but will eventually return to avenge his father’s death.