why does hera send athena down to achilles?

Agamemnon and Achilles represent two opposing forces on the Trojan War:the Achaeans and Troy, respectively. Angered by what he perceived to be a grave dishonor, Achilles aims to kill Agamemnon after the war had been somewhat settled. Hera, who sides with the Achaeans against Troy, sends Athena to Achilles in order to stop him.