The fall of Carthage, and the consequent elevation of Rome, is the second. All the varieties in the fortune of those two famous republics may very well be accounted for from the same cause.
From the end of the first to the beginning of the second Carthaginian war, the armies of Carthage were continually in the field, and employed under three great generals, who succeeded one another in the command; Amilcar, his son-in-law Asdrubal, and his son Annibal: first in chastising their own rebellious slaves, afterwards in subduing the revolted nations of Africa; and lastly, in conquering the great kingdom of Spain. The army which Annibal led from Spain into Italy must necessarily, in those different wars, have been gradually formed to the exact discipline of a standing army. The Romans, in the meantime, though they had not been altogether at peace, yet they had not, during this period, been engaged in any war of very great consequence; and their military discipline, it is generally said, was a good deal relaxed. The Roman armies which Annibal encountered at Trebi, Thrasymenus, and Cannae, were militia opposed to a standing army. This circumstance, it is probable, contributed more than any other to determine the fate of those battles.
The standing army which Annibal left behind him in Spain had the like superiority over the militia which the Romans sent to oppose it; and, in a few years, under the command of his brother, the younger Asdrubal, expelled them almost entirely from that country.
Annibal was ill supplied from home. The Roman militia, being continually in the field, became, in the progress of the war, a well disciplined and well exercised standing army; and the superiority of Annibal grew every day less and less. Asdrubal judged it necessary to lead the whole, or almost the whole, of the standing army which he commanded in Spain, to the assistance of his brother in Italy. In this march, he is said to have been misled by his guides; and in a country which he did not know, was surprised and attacked, by another standing army, in every respect equal or superior to his own, and was entirely defeated.
When Asdrubal had left Spain, the great Scipio found nothing to oppose him but a militia inferior to his own. He conquered and subdued that militia, and, in the course of the war, his own militia necessarily became a well disciplined and well exercised standing army. That standing army was afterwards carried to Africa, where it found nothing but a militia to oppose it. In order to defend Carthage, it became necessary to recal the standing army of Annibal. The disheartened and frequently defeated African militia joined it, and, at the battle of Zama, composed the greater part of the troops of Annibal. The event of that day determined the fate of the two rival republics.
From the end of the second Carthaginian war till the fall of the Roman republic, the armies of Rome were in every respect standing armies. The standing army of Macedon made some resistance to their arms. In the height of their grandeur, it cost them two great wars, and three great battles, to subdue that little kingdom, of which the conquest would probably have been still more difficult, had it not been for the cowardice of its last king. The militias of all the civilized nations of the ancient world, of Greece, of Syria, and of Egypt, made but a feeble resistance to the standing armies of Rome. The militias of some barbarous nations defended themselves much better. The Scythian or Tartar militia, which Mithridates drew from the countries north of the Euxine and Caspian seas, were the most formidable enemies whom the Romans had to encounter after the second Carthaginian war. The Parthian and German militias, too, were always respectable, and upon several occasions, gained very considerable advantages over the Roman armies. In general, however, and when the Roman armies were well commanded, they appear to have been very much superior; and if the Romans did not pursue the final conquest either of Parthia or Germany, it was probably because they judged that it was not worth while to add those two barbarous countries to an empire which was already too large. The ancient Parthians appear to have been a nation of Scythian or Tartar extraction, and to have always retained a good deal of the manners of their ancestors. The ancient Germans were, like the Scythians or Tartars, a nation of wandering shepherds, who went to war under the same chiefs whom they were accustomed to follow in peace. ‘Their militia was exactly of the same kind with that of the Scythians or Tartars, from whom, too, they were probably descended.
Many different causes contributed to relax the discipline of the Roman armies. Its extreme severity was, perhaps, one of those causes. In the days of their grandeur, when no enemy appeared capable of opposing them, their heavy armour was laid aside as unnecessarily burdensome, their laborious exercises were neglected, as unnecessarily toilsome. Under the Roman emperors, besides, the standing armies of Rome, those particularly which guarded the German and Pannonian frontiers, became dangerous to their masters, against whom they used frequently to set up their own generals. In order to render them less formidable, according to some authors, Dioclesian, according to others, Constantine, first withdrew them from the frontier, where they had always before been encamped in great bodies, generally of two or three legions each, and dispersed them in small bodies through the different provincial towns, from whence they were scarce ever removed, but when it became necessary to repel an invasion. Small bodies of soldiers, quartered in trading and manufacturing towns, and seldom removed from those quarters, became themselves trades men, artificers, and manufacturers. The civil came to predominate over the military character; and the standing armies of Rome gradually degenerated into a corrupt, neglected, and undisciplined militia, incapable of resisting the attack of the German and Scythian militias, which soon afterwards invaded the western empire. It was only by hiring the militia of some of those nations to oppose to that of others, that the emperors were for some time able to defend themselves. The fall of the western empire is the third great revolution in the affairs of mankind, of which ancient history has preserved any distinct or circumstantial account. It was brought about by the irresistible superiority which the militia of a barbarous has over that of a civilized nation; which the militia of a nation of shepherds has over that of a nation of husbandmen, artificers, and manufacturers. The victories which have been gained by militias have generally been, not over standing armies, but over other militias, in exercise and discipline inferior to themselves. Such were the victories which the Greek militia gained over that of the Persian empire; and such, too, were those which, in later times, the Swiss militia gained over that of the Austrians and Burgundians.
The military force of the German and Scythian nations, who established themselves upon ruins of the western empire, continued for some time to be of the same kind in their new settlements, as it had been in their original country. It was a militia of shepherds and husbandmen, which, in time of war, took the field under the command of the same chieftains whom it was accustomed to obey in peace. It was, therefore, tolerably well exercised, and tolerably well disciplined. As arts and industry advanced, however, the authority of the chieftains gradually decayed, and the great body of the people had less time to spare for military exercises. Both the discipline and the exercise of the feudal militia, therefore, went gradually to ruin, and standing armies were gradually introduced to supply the place of it. When the expedient of a standing army, besides, had once been adopted by one civilized nation, it became necessary that all its neighbours should follow the example. They soon found that their safety depended upon their doing so, and that their own militia was altogether incapable of resisting the attack of such an army.
The soldiers of a standing army, though they may never have seen an enemy, yet have frequently appeared to possess all the courage of veteran troops, and, the very moment that they took the field, to have been fit to face the hardiest and most experienced veterans. In 1756, when the Russian army marched into Poland, the valour of the Russian soldiers did not appear inferior to that of the Prussians, at that time supposed to be the hardiest and most experienced veterans in Europe. The Russian empire, however, had enjoyed a profound peace for near twenty years before, and could at that time have very few soldiers who had ever seen an enemy. When the Spanish war broke out in 1739, England had enjoyed a profound peace for about eight-and-twenty years. The valour of her soldiers, however, far from being corrupted by that long peace, was never more distinguished than in the attempt upon Carthagena, the first unfortunate exploit of that unfortunate war. In a long peace, the generals, perhaps, may sometimes forget their skill; but where a well regulated standing army has been kept up, the soldiers seem never to forget their valour.