Milton’s Paradise Lost is an epic opem about the origin of evil, mixing classical and Christian forms and sources. This essay first explores whether “evil” is primarily a classical or Judeo-Christian concept, and shows that it is a product of the religious syncretism of the Hellenistic period. Yet among the poets, we meet this new sense of malignance chiefly in Virgil, especially in such a figure as Allecto. The essay then shows how Milton’s language carefully discriminates among these origins, so that the imagery of Hell comes from Virgil, while the conception of evil remains principally Christian, both in the narrative and in philosophical reflection. But in the final section of the essay, we see that the being whose identity is the answer to the poem’s initiating epic question (‘Who first seduc’d them to that foul revolt?’), and whose actions drive the poem into motion and inaugurate its story—Stan—, is, like his daughter Sin, a complex and seductive blend of both—and this helps to explain some of the tension we feel in his presence. He is a much more complex answer than those required by the initiating questions in Homer or Virgil, and indeed it takes the whole poem to understand that answer.