Sentence:  And the "Iliad" was founded on a play of words, the substitution of a couple of letters in a name. <WSD>Briseis</WSD>, Chryseis. The bone of contention that triggers the poem is <WSD>Briseis</WSD> "kallipárēos", <WSD>Briseis</WSD> “of the lovely cheeks”: Agamemnon wants her exchanged with, or substituted for, Chryseis "kallipárēos", Chryseis “of the lovely cheeks." In Greek only two letters separate the two girls. 
Meaning of the word marked with <WSD> tags:  A legendary figure who features in the "Iliad"; a princess granted as concubine to Achilles after the sacking of her city, Lyrnessus, before the beginning of the story.