The _Age of Revival_ begins with the opening of the eleventh century, and ends with the discovery of America by Columbus in 1492. During all this time civilization was making slow but sure advances. The last century of the period, especially, was marked by a great revival of classical learning (known as the _Renaissance_, or New Birth), by improvements, inventions, and discoveries, which greatly stirred men's minds, and awakened them as from a sleep. The Crusades, or Holy Wars, were the most remarkable undertakings of the age. The _Era of the Reformation_ embraces the sixteenth century and the first half of the seventeenth. The period is characterized by the great religious movement known as the Reformation, and the tremendous struggle between Catholicism and Protestantism. Almost all the wars of the period were religious wars. The last great combat was the Thirty Years' War in Germany, which was closed by the celebrated Peace of Westphalia, in 1648. After this date the disputes and wars between parties and nations were political rather than religious in character. The _Era of the Political Revolution_ extends from the Peace of Westphalia to the present time. This age is especially marked by the great conflict between despotic and liberal principles of government, resulting in the triumph of democratic ideas. The central event of the period is the French Revolution. Having now made a general survey of the ground we are to traverse, we must return to our starting-point,--the fall of Rome. RELATION OF THE FALL OF ROME TO WORLD-HISTORY.--The calamity which in the fifth century befell the Roman empire in the West is sometimes represented as having destroyed the treasures of the Old World. It was not so. All that was really valuable in the accumulations of antiquity escaped harm, and became sooner or later the possession of the succeeding ages. The catastrophe simply prepared the way for the shifting of the scene of civilization from the south to the north of Europe, simply transferred at once political power, and gradually social and intellectual preeminence, from one branch of the Aryan family to another,--from the Græco-Italic to the Teutonic. The event was not an unrelieved calamity, because, fortunately, the floods that seemed to be sweeping so much away were not the mountain torrent, which covers fruitful fields with worthless drift, but the overflowing Nile with its rich deposits. Over all the regions covered by the barbarian inundation a new stratum of population was deposited, a new soil formed that was capable of nourishing a better civilization than any the world had yet seen. THE THREE ELEMENTS OF CIVILIZATION.--We must now notice what survived the catastrophe of the fifth century, what it was that Rome transmitted to the new rulers of the world, the Teutonic race. This renders necessary an analysis of the elements of civilization.