Chryseis

Chryseis was the daughter of Chryses, a priest of Apollo.  When the Greeks captured the city of Thebe, a Trojan ally, Chryseis was taken prisoner and Agamemnon claimed her as his prize.  Agamemnon was infatuated with her, and refused to except Chryses' ransom.  As a result, Apollo sent a plague upon the Greeks.

The other Greeks pressured Agamemnon to give up Chryseis, and he finally relented.  As recompense, Agamemnon took Briseis, a concubine of Achilles.  With his pride now injured, Achilles refused to fight.

Source(s):

  1. HomerIliad.