Patroclus died as a true hero in battle. He killed every Trojan he met on his way and saved the Achaean ships. His intervention made the Trojans retreat and started the end of the fortified city. Zeus predicted Patroclus’ death, and there was no way to change his fate.
The reader learns about the imminent Patroclus’ death from Book 15. There, Zeus tells Hera that Troy is doomed and Hector will die soon after he kills Patroclus. But despite these predictions, he will help the Trojans once more.
Apollo helps the Trojans to fight their way to the Greek camp. The ships (which are the only escape route for the Achaeans) are in danger. The Greeks start to panic. Patroclus goes to Achilles and begs him to lend his armor, chariot, and men, as long as Achilles refuses to do anything himself. The hero agrees with a condition. Patroclus should drive the enemy away from the ships and no farther.
The situation is growing tense: while Patroclus puts on Achilles’ armor, the first ship is already burning. Patroclus departs with the Myrmidons, who have remained idle since Achilles was insulted by Agamemnon. Achilles sees him off, praying to Zeus that his friend returns safe and the ships are unharmed.
The appearance of Patroclus in Achilles’ armor made the Trojans retreat. Quick success makes Patroclus disobey his friend, so he chases the enemies all the way to Troy.
Near the city, Patroclus meets Hector in battle. He kills Hector’s charioteer, but then a young soldier wounds him. There was little left to do for Hector. He finishes Paris off while the dying hero tells him that Achilles will come and get revenge.