In Greek mythology, Briseis (in ancient Greek Briseís), is a young Trojan woman, originally from the city of Lyrnessos, kidnapped during the Trojan War by Achilles, after having killed her three brothers and her husband, King Mynes of Lyrnessos.
Her real name is Hippodamia (Hippodámeia), "Briseis" being only a surname meaning "daughter of Briseos".
After an oracle forces Agamemnon to renounce a woman he had captured, Chryseis, the latter sends his two heralds Thaltybios and Eryrates, to seek Briseis in compensation.
Considering himself despoiled, Achilles flew into a great rage and then refused to fight alongside the Greek armies commanded by Agamemnon. He asks Zeus, through his mother Thetis, to grant victory to the Trojans until the Greeks beg him to return to battle. This fatal anger causes many of the most important events of the Trojan War, including the death of Patroclus, lover of Achilles. It is this anger of Achilles that constitutes the subject of the Iliad.
In the Iliad, Briseis is the captive of Achilles, whom the Greek army offered him as a reward. He loves her and compares their relationship to that of a man and his wife, and can't stand the fact that Agamemnon sleeps with her. When the quarrel ends, the latter swears to him that he never slept with Briseis.