This study is in its broadest sense an inquiry into the intellectual origins of the Reformed branch of Protestantism generally, but inaccurately, designated Calvinism. More specifically, it concerns one of the early theologians who gave formative shape to Reformed theology, Peter Martyr Vermigli (1499-1562), and focuses on his adoption of the soteriological doctrine of gemina praedestinatio, double predestination: divine election and divine reprobation.