Explanatio Not only is Achilles upset because he was fond of Briseis, he is also upset because his pride took a hit in front of all the warriors who saw that Agamemnon got the better of him. This causes him to stop fighting.n:
Achilles finds its form as a result of Agamemnon ignoring the priest of Apollo, causing the god to send a plague to the Achaeans. ... This belief causes Agamemnon to take Briseis, a prize rightfully won by Achilles, to claim her as his own.
