Commentary Inf X 130-132

Virgil's promise that Beatrice (it can only be she) will lay bare to him the story of his life to come is not fulfilled, even though it is referred to again at [Inf XV 88-90]. This role, so clearly reserved for Beatrice, is eventually given to Cacciaguida in [Par XVII 46-75]. The apparent contradiction has caused much consternation. An ingenious solution has been proposed by Marguerite Mills Chiarenza (Chia.1983.3): just as in the Aeneid Helenus promises Aeneas that the Sibyl will reveal his future to him (Aen. III.458-460) only to have her instead lead him to Anchises, who performs that promised task (VI.756-886), so, in the Comedy also, the promised female 'prophet' is replaced by a male. In Chiarenza's view, the 'contradiction' is deliberate.