Chaucer claimed to be no more than a "lewd compilator" of other voices. All creators steal. From a recent "review" of Canterbury Tales:
Three Italian poets: Petrarch, Boccaccio (both of whom Chaucer may have met on a trip to Italy in 1373) and Dante. Boccaccio’s “Decameron” lent the inspiration and narrative template for “The Canterbury Tales”. More technically, Geoffrey de Vinsauf’s “Poetria Nova”, a passage from which Chaucer lifted for “Troilus and Criseyde”, armed him with rhetorical devices.
We are Chaucer fans here at Maggie's. I prefer to hear it read, rather than to read it. Audio of a modern translation here. When I was in school, we did it in the original and had good fun with it.