You are nowadays called upon to acquire so great a mass of learning and information in the period of life between the ages of twelve and eighteen that it is not surprising that but little time can be spared for the study of the history of foreign nations. Most lads are, therefore, lamentably ignorant of the leading events of even the most important epochs of Continental history, although, as many of these events have exercised a marked influence upon the existing state of affairs in Europe, a knowledge of them is far more useful, and, it may be said, far more interesting than that of the comparatively petty affairs of Athens, Sparta, Corinth, and Thebes. Prominent among such epochs is the Thirty Years' War, which arose from the determination of the Emperor of Austria to crush out Protestantism throughout Germany. Since the invasion of the Huns no struggle which has taken place in Europe has approached this in the obstinacy of the fighting and the terrible sufferings which the war inflicted upon the people at large. During these thirty years the population of Germany decreased by nearly a third, and in some of the states half the towns and two-thirds of the villages absolutely disappeared.