Agamemnon was the written by Aeschylus in Ancient Greece, and recounts the events in the city of Argos after Agamemnon's return from the Trojan War.
The play begins with a watchman on the roof of the palace at Argos, waiting to hear of the fall of Troy from the Greek armies. He is notified by a beacon of the fall of Troy and goes to tell Clytemnestra. At this time, the Chorus enters and tells the story of how Paris, Prince of Troy, stole Helen, the wife of the Greek king Menelaus, thus sparking the Trojan War. The Chorus also tells of how Agamemnon, Clytemnestra's husband, sacrificed their daughter to the god Artemis to gain a favorable wind for the Greek ships to reach their destination in Troy.
Clytemnestra calls for sacrifices of thanksgiving to the gods and the Chorus questions her decision. She states that Troy has fallen and Agamemnon has returned, knowing this from the beacon, so the Chorus gives thanks and wonders if it is true until confirmed by a herald.
Agamemnon returns, bringing along with him a princess named Cassandra he has taken from Troy. Clytemnestra welcomes him and professes her love for him, asking him to enter the palace. Agamemnon does so, and Clytemnestra asks Cassandra to follow. Cassandra speaks with the chorus, telling them of a curse on Agamemnon's house before she enters. She tells of her death and the death of Agamemnon and the coming of an avenger and enters the palace. Shortly after, Clytemnestra appears with Aegisthus, her lover and Agamemnon's cousin, after killing her husband and Cassandra, and the two take over the government.
One of the issues in the play I happened to notice after reading the play and comparing it to events in the Iliad is the ability for some characters to know fates and how they accept them. This makes for a great tragedy, and the reader has a sense of helplessness and despair while following the plot.
In the Iliad, for example, Achilles and Hector both know the outcome of the war the entire time that they are battling yet continue to fight anyway.