As I mentioned in my post on Monday, The Iliad begins when military commander Agamemnon takes Achilles' slave woman to be his own companion. Achilles flies into a rage and refuses to continue fighting in the battles against Troy. Reading The Iliad with the eyes of a modern person, Achilles' action makes him seem childish or petty, sulking in his tent and being quite the drama queen. But Homer intended for his readers to take away a deeper message.
In order to understand the why Achilles got so angry, it is necessary to understand a little about ancient Greek culture. Greek military society revolved around the polar concepts of honor and shame. Men were taught to value their position in society and to make sure that they did nothing that would bring on the condemnation of others. In our modern culture, we tend to emphasize the more internal emotions of pride and guilt, but the Greeks believed that what other people said about you was an indication of your true worth. If one's honor is impugned, one's entire identity can be lost.
Briseis, the slave woman, was an honor-reward for Achilles--a prize meant to express Agamemnon's approval of the young soldier's heroism in war. Removing her from his tent was seen by Achilles as an act meant to shame him.
In the case of Achilles, the story gets even more complex. He knew that his great prowess as a soldier meant that he was fated to die in war. The gods had promised that his death would be rewarded with fame and honor that would last through the generations. Achilles fought because this bargain was his fate, not out of patriotic commitment. When Agamemnon retracts the reward Achilles has been given, the young soldier sees that the divine bargain has broken down. Since he is not receiving the honor, he believes he should not have to die. In other words, Achilles refuses to fight not because he doesn't like being insulted but because his entire reason to fight in the first place has just been removed.
The Greek military prized a hierarchical system of command that did not allow subordinates to challenge those in charge. Achilles felt he had the right to stand up in opposition to his commander--that is, to be insubordinate--only because he felt that Agamemnon had violated proper adherence to the system of honor-rewards ingrained in the culture.
Achilles begins to transcend this rage only by rejecting the system of honor and shame that lay at the heart of Ancient Greece. After the death of his beloved friend Patroclus, Achilles reenters the war against the Trojans--this time for vengeance rather than for honor. He is no longer acting out of a willingness to follow the dictates of fate. He is no longer acting out of a desire to be a hero. Achilles picks up his shield because his heart is broken. He feels guilt for not protecting Patroclus, his Myrmidons, and all of the Greeks. Although as a pacifist I am horrified by the violent anger of Achilles, I am nonetheless moved to tears by this reconnection to community, to connection, to his human self.