=The Revival of Platonism.= The Platonism of the Academy had had little influence in the Ethical Period and its tradition had been barely kept alive. The Middle Academy had been skeptical and the New Academy eclectic. The Religious Period, on the other hand, was thoroughly Platonic, and Plato from this time until the Crusades became the ruling philosophical power. For three hundred years his influence had been nothing; for the next twelve hundred he dominated men’s minds, so far as any philosopher could in religious times. When the Wise Man vanished from philosophy, and the expectation of spiritual blessedness took its place, when Skepticism drove men from ethics, first to eclecticism and then to theology, when philosophy passed to mysticism――then did Platonism, with its antithesis between the sensible and the supersensible, come to its own. Of all the historical philosophies it could best amalgamate all religions. Platonism (1) absorbed Oriental religions, (2) furnished a didactic form for Christianity, (3) recreated itself into the mystic neo-Platonism. The world-longing for the supernatural found its best medium in Platonism. When the Wise Man vanished, the mystic priest appeared. =The Divisions of the Religious Period.= Out of the seething religious times at the beginning of this era, there emerged two distinct currents of thought that extended through the entire length of the Religious Period, and carried down into the Middle Ages all the culture that the mediæval possessed. The two movements were (1) the religious philosophies of the still persistent Hellenic civilization, and (2) the new-born Christian religion, which was destined to determine the future of the western people. If we scrutinize these two movements we shall find that each has its introductory and its development stages, and at the point of division in each stands a great leader who was instrumental in bringing about the transition. The great neo-Platonist, Plotinus (204–269), marks the division line in the Hellenic movement; the Christian, Origen (185–254), marks the division line in theological Christianity. While these men were contemporaries, we shall take, for various reasons, the year 200 as the date of division of the Christian movement, and the year 250 as the date of division of the Hellenic movement. The first stage of each movement we shall call its Introductory Period, and the second its Development Period.