The thirteenth century was one of the great centuries of Christian history. In it feudalism reached its height, and chivalry its fullest flower. In it Gothic architecture and medieval philosophy reared their noblest monuments. It was the century of the greatest of medieval, or, perhaps, of distinctively Christian, poets, Dante, the greatest of Christian theologians, Aquinas, the greatest of Popes, Innocent III., the two most winsome of saints, St. Francis and St. Louis of France. In all its greatness, the thirteenth century is distinctively Roman Catholic. The nineteenth century, also, is another of the less than half a dozen of the greatest of Christian centuries, and it is distinctively a Protestant century. Its great achievements in geographical and astronomical discovery, scientific investigation, increase of human comfort and wealth, and above all its unparalleled extension of liberty--bear all of them the Protestant stamp. These two centuries have thus established beyond dispute the right of those two great historic forms of Christianity to the lasting reverence and gratitude of mankind. Roman Catholicism has cherished the divine principle of unity. At great cost it has preserved unity. It has not been equally careful of the divine principle of liberty. Protestantism has gloriously fought and suffered and died for liberty. It has never highly valued unity. It has even gloried in division. But unity is a diviner thing than even liberty. Liberty is precious only as the indispensable condition and pre-requisite of true unity. It is a lovely and thrilling hope that the twentieth century may prove to be the century of the Great Christianity, the Christianity which will extinguish neither Latin nor Teutonic Christianity but comprehend and blend them, the simple, yet free and varied, democratic, passionate Christianity of all who love the Lord Jesus Christ and seek His Kingdom on the earth, the Christianity which was the first and will be the last. This, at least, can be said, that the unparalleled problems of social and political reconstruction facing the world to-day can be rightly solved only by a great religious devotion, and it is difficult to see how that devotion can be secured except by a unification of the great Churches of Christendom and their common baptism into the spirit of primitive Christianity. And let no one say the Great Christianity is only a beautiful dream.