Content Decline of roman empire and the rise of Christianity Saint Augustine: City of God Saint Thomas Aquinas: God and Human Being Conflict between church and king Church and medieval FeudalismContent ◼ Decline of Roman Empire and the rise of Christianity ◼ Saint Augustine: City of God ◼ Saint Thomas Aquinas: God and Human Being ◼ Conflict between church and king ◼ Church and Medieval Feudalism