In the movie Brad Pitt acted as Achilles, son of Peleus and Thetis, cousin of Patroclus, and leader of the Myrmidons. He is also the lover of Briseis.
Brian Cox acted as Agamemnon, the king of Mycenae. He is the brother of Menelaus.
Brendan Gleeson acted as Menelaus, the king of Sparta and husband of Helen. He is the brother of Agamemnon.
Peter O'Toole acted as Priam, the king of Troy, father of Hector and Paris, uncle of Briseis and father-in-law of Andromache.
Eric Bana acted as Hector, the prince of Troy and the best warrior among the Trojans. He is the elder son of Priam, brother of Paris, cousin of Briseis and husband of Andromache.
Orlando Bloom acted as Paris, the prince of Troy. He is the younger son of Priam, brother of Hector, cousin of Briseis and brother-in-law of Andromache. He is the lover of Helen.
Diane Kruger acted as Helen, the queen of Sparta and wife of Menelaus. She is the lover of Paris.
Agamemnon wants all of Greece to himself, so he does what any good ruler would do, and that is attack anyone and everyone. His brother, the King of Sparta meanwhile, is trying to broker a peace agreement with Troy. But one of the peacekeepers, Prince Paris falls in love with the King's wife, Helen, and brings her back to Troy. This of course pisses off the King to no end, and with his brother, they launch a massive attack on Troy. But they know the only way they can win is to have the mighty Achilles on their side, and Achilles doesn't like Agamemnon. Achilles does join the fight and has a few showdowns with his equal, Prince Hector of Troy. The battles are massive and Troy looks to be on the winning end. But with the help of the famous Trojan horse, things are not quite what they appear to be.