“Agamemnon is compelled to restore the captive girl Chryseis to her father, but in retaliation takes from Achilles the lovely Briseis. Achilles, enraged, vows he will fight no more for Agamemnon and through his mother, the sea nymph Thetis, secures the aid of Zeus for the Trojans. This provokes the wrath of the goddess Hera.”
From the Iliad, book one

“Sing, O Goddess, the anger of Achilles, so of Peleus, that brought countless ills upon the Achaens. Many a brave soul did it send hurrying down to Hades, and many a hero did it yield a prey to dogs and vultures, for so were the counsels of Zeus fulfilled from the day on which the son of Atreus, king of men, and great Achilles first fell out with one another.
From the Illiad, on the back