Chaucer begins the final book with an invocation of the three fates, particularly Lachesis, who stretches out the thread of Troilus’ lifespan. Criseyde is led out of Troy, and Troilus watches for as long as he can with her escort. She is taken by a Greek named Diomede, and Antenor is returned in her staid. As Criseyde and Diomede ride back to the Greek camp, Diomede pledges his service to her and swears that he has involuntarily fallen in love with her. Criseyde is grieving and barely hears what he is saying before they reach her father’s tent.

Back in Troy, Troilus returns to his rooms and begins to weep and rage again. He begs for death to take him, feeling that he cannot endure 10 days without Criseyde. When Pandarus comes to visit him, he tells Pandarus to help him plan his funeral and asks him to take the ashes of his heart to Criseyde in a golden urn once he is dead. Pandarus scolds him, reminding him that many people have endured even longer periods of separation from their lovers. He advises Troilus to try to focus on happiness and enjoyment so that the time will pass faster.