The idea of progress has become one of the central concepts of western civilization; but in the ante-Nicene period, this idea, with its inherent optimism, was little known. The universe was controlled by supernatural forces which were often working against man. Fate and the stars controlled the lives of men, but controlling the stars were demons. These pages review pagan and Christian demonology from Plato to Iamblichus. During these centuries, there were variations among the pagans in the concept of the function and nature of demons; but the answers to the three main philosophic questions implicit in demonology -- the problem of evil, the problem of unity and diversity, and the relationship of the soul to a higher sphere -- remained remarkably the same. Christianity, because of a different view of the universe, answered these questions in a different way. The early Christians, from Paul to Lactantius, proclaimed victory over the demonic forces which held the pagan world in fear. By the cross of Jesus Christ, the power of the demonic forces which had enslaved men was broken. The major battle against the forces of evil had been won; and the cross was a positive token that ultimately a kingdom would be established in which demons had no power. Among the Christians, the despair of the pagan world was replaced by an eschatological hope.