Briseis played a great role in the Trojan war because she was the reason that Achilles refused to fight with  the Greeks after his anger with the King Agamemnon. Briseis was the wife of Brisseus king of the Lelegs. When Achilles conquer the city of Lirnissos took as prisoner Briseis. She became Achilles beloved slave, but when Agamemnon had to give back his maid Cressida demanded from Achilles to give him Briseis. That caused a great anger to Achilles and therefore he refused to fight. The episode was one of the most significant of the Trojan war because it caused the death of his best friend Patroclus by Hector, when he tried to imitate Achilles wearing his armour.

Cressida was the daughter of the priest and seer Calchas of Troy. She was very beautiful, and was loved by Troilus.When Calchas defected to the Greeks, Cressida stayed in Troy and was treated well. Calchas managed to get Agamemnon to ask king Priamfor Cressida, and the Trojan king had her escorted to the Greek camp by several of his sons.Even though she was betrothed to Troilus, she fell in love with Diomedes the Argive. Her love was returned, and Diomedes did everything he could to kill Troilus every time they met on the battlefield.