The nonexistence of Achilles from the battle only lasted a couple of days and the epic ended shortly afterwards. The way I interpreted the poem it did not describe the origin or the end of the war that frames Achilles wrath. The main focus of this poem was the rage of a mortal which is also the heading of the poem. Another focus was also was the motivation and action of the gods. Before Homer goes into great depth regarding the quarrel between Achilles and Agamemnon, he explained that he felt that Apollo was responsible for the conflict.
The conflict between Agamemnon and Achilles highlights one of the strongest aspects of the ancient Greek systems. Agamemnon thought that as chief of the Achaean forces, he should receive the highest prize he was willing to upset Achilles. Both men Agamemnon and Achilles considered not embarrassing the other and decided to put their own interest before that of the people, which jeopardize the efforts of the war. The Iliad (Book XVI) This book refers to the death of Patroclus. Zeus comforts Poseidon after Hera tried to blame her for the havoc that was caused while Zeus was in a deep sleep.
Zeus informed Poseidon that Hector will die after he kills Patroclus. Hector leads a charge against Achaeans after Apollo fills him and his soldiers with strength. The two armies fought almost to the Greek camps, but did reach the ships and Hector rallied the Trojans and inch by inch the Trojans advance until Hector is close enough to touch the ships. According to the books Hector stripped Achilles divine armor from Patroclus’s corpse and the fierce fight ended in partial success for the Greeks (pg 158).