What did the Greek army do to make Athena angry?

When the Greeks sacked Troy, they found Cassandra, daughter of King Priam of Troy, clinging to a statue in Athena's temple. Ajax the Lesser dragged her from the temple, and by some accounts raped her. Cassandra was then given to Agamemnon as a concubine. As punishment for defiling her temple and abusing her follower, Athena and Poseidon created huge storms that drove the Greek fleet off course, and killed Ajax.