King of Mycenae and leader of the Greek armies in the Trojan War. He was the son of Atreus, on whose house a curse had been laid.
Clytemnestra was his wife, and together they had two sons, Orestes and Chrysothemis, and two daughters, Iphigenia and Electra. Agamemnon sacrificed Iphigenia to Artemis, so that the Greeks would succeed in the war against Troy. He left Clytemnestra with a singer, and as long as the singer was present, she resisted Aegisthus. Aegisthus then took the singer to a deserted island, and Clytemnestra was seduced.

During the ten year siege of Troy, the Greeks had looted many cities. At one of them, Chryse, Agamemnon had taken the priest of Apollo Chryses daughter Chryseis. When the priest came to him in order to buy back his daughter Agamemnon refused. Chryses then invoked Apollo to punish the king, and the god descended from the skies, shooting arrows of plague among the Greeks.
Achilles learned the cause of all this, and forced Agamemnon to return the girl, directing the kings wrath upon himself. Agamemnon then took the captive maiden Briseis from Achilles, which caused the hero to almost leave the war, and later he was to take the infamous Cassandra back with him to Mycenae.
Once home he was murdered in his bath or at dinner by Clytemnestra and her lover Aegisthus, and was avenged by Orestes seven years later. The story of Agamemnon and Orestes revenge was the inspiration for William Shakespeare when he wrote Hamlet.