Dante's vision of history in the Divine Comedy is a radical reworking of both Vergil and Augustine, generating a notion of the earthly city to supplant the quite different Roman constructions of his two Latin forebears. What has not been noted, however, is the strategic placement of this revision at the center of the poem. Undergirding Purgatorio 13-17 is Augustine's meditation on Cain and Abel taken out of the anti-Roman polemic of the City of God and translated into Dante's own political vernacular. It is in Purgatorio 15, moreover, that Augustine is introduced to us—not in person, but through an extended paraphrase of City of God 15.5 that is placed in Vergil's mouth. While Augustine surfaces textually at this point, he does so through the mediation of the poet of empire. The maneuver reveals yet another dimension of Dante's power over his authorities—the politics of his poetics.