tended like a huge crescent from Spain over Northern Africa, Egypt, Palestine, Arabia, Persia, and Syria, to the eastern part of Asia Minor. The danger which this fanatic religion offered to Christian faith, in countries where the two religions came in contact, was not to be treated lightly. And so we find a series of apologies written to uphold the truth of Christianity in the face of Moslem errors. Perhaps the earliest was the "Discussion between a Saracen and a Christian" composed by St. John Damascene (about 750). In this apology he vindicates the dogma of the Incarnation against the rigid and fatalistic conception of God taught by Mohammed. He also demonstrates the superiority of the religion of Christ, pointing out the grave defects in Mohammed's life and teaching, and showing the Koran to be in its best parts but a feeble imitation of the Sacred Scriptures. Other apologies of a similar kind were composed by Peter the Venerable in the twelfth, and by Raymond of Martini in the thirteenth century. Hardly less dangerous to the Christian faith was the rationalistic philosophy of Islamism. The Arabian conquerors had learned from the Syrians the arts and sciences of the Greek world. They became especially proficient in medicine, mathematics, and philosophy, for the study of which they erected in every part of their domain schools and libraries. In the twelfth century Moorish Spain had nineteen colleges, and their renown attracted hundreds of Christian scholars from every part of Europe. Herein lay a grave menace to Christian orthodoxy, for the philosophy of Aristotle as taught in these schools had become thoroughly tinctured with Arabian pantheism and rationalism. The peculiar tenet of the celebrated Moorish philosopher Averroes was much in vogue, namely: that philosophy and religion are two independent spheres of thought, so that what is true in the one may be false in the other. Again, it was commonly taught that faith is for the masses who cannot think for themselves, but philosophy is a higher form of knowledge which noble minds should seek to acquire. Among the fundamental dogmas denied by the Arabian philosophers were creation, providence, and immortality. To vindicate Christianity against Mohammedan rationalism, St. Thomas composed (1261–64) his philosophical "Summa contra Gentiles", in four books. In this great apology the respective claims of reason and faith are carefully distinguished and harmonized, and a systematic demonstration of the grounds of faith is built up with arguments of reason and authority such as appealed directly to the minds of that day. In treating of God, providence, creation and the future life, St. Thomas refutes the chief errors of the Arabian, Jewish, and Greek philosophers, and shows that the genuine teaching of Aristotle confirms the great truths of religion. Three apologies composed in much the same spirit, but belonging to a later age, may be mentioned here. The one is the fine work of Louis Vivés, "De Veritate Fidei Christianæ Libri V" (about 1530). After treating the principles of natural theology, the Incarnation, and Redemption, he gives two dialogues, one between a Christian and a Jew, the other between a Christian and a Mohammedan, in which he shows the superiority of the Christian religion. Similar to this is the apology of the celebrated Dutch theologian Grotius, "De Veritate Religionis Christianæ" (1627). It is in six books. An able treatise on natural theology is followed by a demonstration of the truth of Christianity based on the life and miracles of Jesus, the holiness of His teaching, and the wonderful propagation of His religion. In proving the authenticity and trustworthiness of the Sacred Scriptures, Grotius appeals largely to internal evidence. The latter part of the work is devoted to a refutation of paganism, Judaism, and Mohammedanism. An apology on somewhat similar lines is that of the Huguenot, Philip deMornay, "De la vérité de la religion chrétienne" (1579). It is the first apology of note that was written in a modern tongue.
Third Period. Catholicism in conflict with Protestantism. The outbreak of Protestantism in the beginning of the sixteenth century, and its rejection of many of the fundamental features of Catholicism, called forth a mass of controversial apologetic literature. It was not, of course, the first time that the principles of Catholic belief had been questioned with reference to Christian orthodoxy. In the early ages of the Church heretical sects, assuming the right to profess allegiance and fidelity to the spirit of Christ, had given occasion to St. Irenæus "On Heresies", Tertullian "On Prescription against Heretics," St. Vincent of Lérins, in his "Commonitory", to insist on unity with the Catholic Church, and, for the purpose of confuting the heretical errors of private interpretation, to appeal to an authoritative rule of faith. In like manner, the rise of heretical sects in the three centuries preceding the Reformation led to an accentuation of the fundamental principles of Catholicism, notably in Moneta's "Summa contra Catharos et Waldenses" (about 1225), and Torquemada's "Summa de Ecclesiâ" (1450). So to a far greater extent, in the outpouring from many sources of Protestant ideas, it became the duty of the hour to defend the true nature of the Church of Christ, to vindicate its authority, its divinely authorized hierarchy under the primacy of the Pope, its visibility, unity, perpetuity, and infallibility, along with other doctrines and practices branded as superstitious.
In the first heat of this gigantic controversy the writings on both sides were sharply polemic, abounding in personal recriminations. But towards the close of the century there developed a tendency to treat the controverted questions more in the manner of a calm, systematic apology. Two works belonging to this time are especially noteworthy. One is the "Disputationes de controversiis Christianæ Fidei" (1581–92), by Robert Bellarmin, a monumental work of vast erudition, rich in apologetic material. The other is the "Principiorum Fidei Doctrinalium Demonstratio" (1579), by Robert Stapleton, whom Döllinger pronounced to be the prince of controversialists. Though not so erudite, it is more profound than the work of Bellarmin. Another excellent work of this period is that of Martin Becan, "De Ecclesiâ Christi" (1633).
Fourth Period. Christianity in conflict with Rationalism.—(a) From the Middle of the Seventeenth to the Nineteenth Century. Rationalism——the setting up of the human reason as the source and measure of all knowable truth—is, of course, not confined to any one period of human history. It has existed from the earliest days of philosophy. But in Christian society it did not become a notable factor till the middle of the seventeenth century, when it asserted itself chiefly in the form of Deism. It was associated, and even to a large extent identified with the rapidly growing movement towards greater intellectual freedom which, stimulated by fruitful scientific inquiry, found itself seriously hampered by the narrow views of inspiration and of historic Bible-interpretation which then prevailed. The Bible had been set up as an infallible source of knowledge not only in matters of religion, but of history, chronology, and physical science. The result was a reaction against the very essentials of Christianity. Deism became the intellectual fashion of the day, leading in many cases to downright atheism. Starting with the principle that no religious doctrine is of value that cannot be proved by experience or by philosophical reflection, the Deists admitted the existence of a God external to the world, but denied
