What event quells the rage of Achilles?

The rage of Achilles is quelled by the death of his close friend Patroclus during the Trojan War. Overcome with grief and anger, Achilles returns to battle to avenge Patroclus by killing Hector, the Trojan prince responsible for his friend's death. This act of vengeance helps to channel his rage into a more focused purpose, ultimately leading to his reconciliation with the consequences of his anger.