Agamemnon took the daughter of the priest Chryseis as a prize. Chryseis offered a good ransom and appealed return of his daughter that was denied by Agamemnon and accepted to ask Appollo to cut down the Ahaeans with a plague instead. (The Iliad: Character Summary of Homer's The Iliad) .

             Achilles was greatly hurt by Agammemnon's selfish behavior and stresses upon return of the girl and threatened not to participate in the war of Menelaus. Agamemnon agrees to return Chryeseis however, in return takes away Briseis the wife of Achilles. Achilles was emotionally broken of this event and appeals his mother- the sea nymph Thetis, to intervene in his favor by reminding of an old debt owed her by Zeus and asking him to obstruct the progress of Achaeans in order to punish Agamemnon. Thetis approached Zeus to satisfy the appeals of her son and Zeus assured against the will of his wife Hera, who has a soft corner of Achaean cause. The war continued while Achilles was brooding at home. Achaeans could succeed in bringing down hard upon the Trojans even without the Achilles. .

             The Trojan leader Hector had to return and pray and offer sacrifices to gods for shifting their luck. Soon there is a turn in the Trojan War in favor of Trojans. The Achaeans had no other alternatives but to request Achilles to join the war. Achilles refuses, however, allows Patroclus his dear friend to lead the army on his behalf, being dressed with his own personal arms. Patroclus fighting bravely could succeed in turning the battle in the Achaean's favor however, with interferences of Appollo he was killed by Hector. The death of his friend impelled Achilles to return to the battle so as to inflict retribution upon Hector. However, Achaean had no arms, as Hector had stripped them off the body of Patroclus. His mother Thetis had to beg the smith of the gods, Hephaestus to prepare a new armor and mighty shield for Achilles. The revengeful Achilles at last returned to the battle, ruthlessly slaying several Trojans.