Fate and divine providence is a major thematic concern in Troilus and Criseyde. Throughout the text, Chaucer explores the question of whether mortals can control their own destiny or whether everything that happens is divinely predetermined. This theme intersects with the romantic story, as Chaucer implies that humans have little choice in who they love, being subject to the power of their own natures or the will of the gods.

From the beginning of the text, the idea of fate drives the plot. Criseyde’s independent but precarious social position in Troy is the result of her father’s ability to see the future: Calkas uses astronomical calculations to determine with certainty that Troy will lose the war, and this foreknowledge leads him to desert the city, leaving his daughter in charge of her own life and fortunes as young women of her time and place rarely were. Calkas’s choice to desert Troy and join its enemies is a drastic one, driven by his certainty that nothing anyone can do will change the war’s preordained outcome. At the same time, this knowledge grants him a freedom of choice that others do not have—knowing what will happen to Troy, he can choose to disregard honor and save himself by joining the winning side.