Agamemnon, however, does not give up his prize willingly, and insists that some other "prize" should be given in exchange. He demands Briseis, the woman given to Achilles in the same siege. Achilles is so angry with Agamemnon for taking Briseis that he immediately withdraws himself and his troops from the fighting with Troy. He also asks his mother, the goddess Thetis, to plead with Zeus to help him avenge the wrong. Zeus agrees to assist the Trojans in their attack on the Achaians, thus showing Agamemnon that Achilles is a indispensable man, who would be the pivot to succeed in battle.
Agamemnon gathers the rest of his army for a massive attack against the Trojans. The first day of battle opens with a duel between Paris and Menelaos, and a truce among the rest of the armies. After the duel, which ends with Paris being taken out of the battle by Aphrodite, the truce is broken by Pandaros, the Trojan, and the two armies engage in bitter fighting. At the end of the day, there is another duel, this time between Aias and Hector, which is broken up before its end. The two sides retreat, and the Achaians build a wall around their encampment to protect their position and their ships.
When fighting resumes, Zeus pushes the Trojans to great triumph over the Achaians, and their victory sseems certain. At this point, Agamemnon calls his leaders together and admits he was at fault in taking Briseis from Achilles. He agrees to return her, along with a great deal of treasure and a sworn oath that he has not slept with her, if Achilles will come back and fight with the Achaians. The message is brought to Achilles by his good friends Odysseus, Aias, and Phoinix. Achilles greets his friends warmly, but still refuses to make peace with Agamemnon.
The next day the fighting resumes, and the Achaians fight bravely. However, over the span of the day, most of the best men are injured and taken out of the fight.