Although the general fabric of the Christian philosophy which was thus built up was in the main Platonic, not a little was borrowed also from the system of the Stoics, especially on the border ground between metaphysics and ethics. This paved the way for a further synthesis, accomplished more easily, more thoroughly, and with less perceptible controversy than had attended either of the others. Probably the culmination of this conquest of the Christian Church by the ethics of the Stoa was reached by Ambrose, who gave to the Christian world Cicero's popularisation of Panaetius and Posidonius in a series of sermons which extracted the {10} ethics of Rome from the scriptures of the Christians. The ethics of the Stoics were almost wholly adopted by the leaders of Christian thought, especially in the West, and the teaching of Jesus as represented in the Gospels was interpreted in the interests of this achievement, which, like the other syntheses, was largely effective in proportion as it was unconscious. Probably it was the early stages of this movement which had rendered possible the acceptance by one another of Christianity and the Empire. Certainly there is still much need of study, even if it produce only the statement of problems, as to the changed character of Christianity between the time of Tertullian and Eusebius. The next few centuries, so far as they were not occupied in struggling against the eclipse of civilisation which began in the fifth century, were occupied in working out the implications of these syntheses. The results were codified in Catholic theology and in the civil and canon law of the early Middle Ages. But one more step remained; after nearly a thousand years Aristotle was rediscovered, and the final achievement of Christian theology was the synthesis effected by St. Thomas Aquinas between the Christian theology and the philosophy of Aristotle. It is a great record of great achievement, for no one who studies the history of religions with any degree of sympathetic insight can doubt but that each synthesis was a real step in progress towards that unification of aspiration with knowledge which {11} it is the task of theologians to bring about, and to express as clearly as they may.