Religious condition of the Roman Republic.--The adoption of imperialism leads to monotheism.--Christianity spreads over the Roman Empire.--The circumstances under which it attained imperial power make its union with Paganism a political necessity.--Tertullian's description of its doctrines and practices.--Debasing effect of the policy of Constantine on it.--Its alliance with the civil power.--Its incompatibility with science.--Destruction of the Alexandrian Library and prohibition of philosophy.-- Exposition of the Augustinian philosophy and Patristic science generally.--The Scriptures made the standard of science. IN a political sense, Christianity is the bequest of the Roman Empire to the world. At the epoch of the transition of Rome from the republican to the imperial form of government, all the independent nationalities around the Mediterranean Sea had been brought under the control of that central power. The conquest that had befallen them in succession had been by no means a disaster. The perpetual wars they had maintained with each other came to an end; the miseries their conflicts had engendered were exchanged for universal peace. Not only as a token of the conquest she had made but also as a gratification to her pride, the conquering republic brought the gods of the vanquished peoples to Rome. With disdainful toleration, she permitted the worship of them all. That paramount authority exercised by each divinity in his original seat disappeared at once in the crowd of gods and goddesses among whom he had been brought. Already, as we have seen, through geographical discoveries and philosophical criticism, faith in the religion of the old days had been profoundly shaken. It was, by this policy of Rome, brought to an end. MONOTHEISM IN THE ROMAN EMPIRE. The kings of all the conquered provinces had vanished; in their stead one emperor had come. The gods also had disappeared. Considering the connection which in all ages has existed between political and religious ideas, it was then not at all strange that polytheism should manifest a tendency to pass into monotheism. Accordingly, divine honors were paid at first to the deceased and at length to the living emperor. The facility with which gods were thus called into existence had a powerful moral effect. The manufacture of a new one cast ridicule on the origin of the old Incarnation in the East and apotheosis in the West were fast filling Olympus with divinities. In the East, gods descended from heaven, and were made incarnate in men; in the West, men ascended from earth, and took their seat among the gods. It was not the importation of Greek skepticism that made Rome skeptical. The excesses of religion itself sapped the foundations of faith.