once boasted of a military force equal in the number of soldiers to that wielded by the Emperor Tiberius. Twenty-five Roman legions made the conquest of the world, and retained that conquest for five hundred years. The self-sustained energy of Caesar in Gaul puts to the blush the efforts of all modern generals, unless we except Frederic II., Marlborough, Napoleon, Wellington, Grant, Sherman, and a few other great geniuses whom warlike crises have developed; nor is there a better text-book on the art of war than that furnished by Caesar himself in his Commentaries. The great victories of the Romans over barbarians, over Gauls, over Carthaginians, over Greeks, over Syrians, over Persians, were not the result of a short-lived enthusiasm, like those of Attila and Tamerlane, but extended over a thousand years. The Romans were essentially military in all their tastes and habits. Luxurious senators and nobles showed the greatest courage and skill in the most difficult campaigns. Antony, Caesar, Pompey, and Lucullus at home were enervated and self-indulgent, but at the head of their legions they were capable of any privation and fatigue. The Roman legion was a most perfect organization, a great mechanical force, and could sustain furious attacks after vigor, patriotism, and public spirit had fled. For three hundred years a vast empire was sustained by mechanism alone. The legion is coeval with the foundation of Rome, but the number of the troops of which it was composed varied at different periods. It rarely exceeded six thousand men; Gibbon estimates the number at six thousand eight hundred and twenty-six men. For many centuries it was composed exclusively of Roman citizens. Up to the year B.C. 107, no one was permitted to serve among the regular troops except those who were regarded as possessing a strong personal interest in the stability of the republic. Marius admitted all orders of citizens; and after the close of the Social War, B.C. 87, the whole free population of Italy was allowed to serve in the regular army. Claudius incorporated with the legion the vanquished Goths, and after him the barbarians filled up the ranks on account of the degeneracy of the times. But during the period when the Romans were conquering the world every citizen was trained to arms, like the Germans of the present day, and was liable to be called upon to serve in the armies. In the early age of the republic the legion was disbanded as soon as the special service was performed, and was in all essential respects a militia. For three centuries we have no record of a Roman army wintering in the field; but when Southern Italy became the seat of war, and especially when Rome was menaced by foreign enemies, and still more when a protracted foreign service became inevitable, the same soldiers remained in activity for several years. Gradually the distinction between the soldier and the civilian was entirely obliterated. The distant wars of the