Answer:
He must return Chryseis to her father.
Step-by-step explanation:
When the war between Greece and Troy turns 10 years old, Agamemnon starts a war against Achilles. However, there is a pestilence that is ending the Greek army, making it difficult for Agamemnon to advance his goals. The plague interrupted the Greek attack and was putting the campaign at risk, so Agamemnon decided to ask the Apollo priest, who promised to end the plague, if Agamemnon repaid his daughter (Chryseis) and took her back to him.