Half-civilised Tartars, the republics of ancient times, the feudal lords and commercial cities of the Middle Ages, kings of the eighteenth century, and, lastly, princes and people of the nineteenth century, all carry on war in their own way, carry it on differently, with different means, and for a different object.

The Tartars seek new abodes. They march out as a nation with their wives and children, they are, therefore, greater than any other army in point of numbers, and their object is to make the enemy submit or expel him altogether. By these means they would soon overthrow everything before them if a high degree of civilisation could be made compatible with such a condition.

The old republics, with the exception of Rome, were of small extent; still smaller their armies, for they excluded the great mass of the populace; they were too numerous and lay too close together not to find an obstacle to great enterprises in the natural equilibrium in which small separate parts always place themselves according to the general law of nature: therefore their wars were confined to devastating the open country and taking some towns in order to ensure to themselves in these a certain degree of influence for the future.

Rome alone forms an exception, but not until the later period of its history. For a long time, by means of small bands, it carried on the usual warfare with its neighbours for booty and alliances. It became great more through the alliances which it formed, and through which neighbouring peoples by degrees became amalgamated with it into one whole, than through actual conquests. It was only after having spread itself in this manner all over southern Italy, that it began to advance as a really conquering power. Carthage fell, Spain and Gaul were conquered, Greece subdued, and its dominion extended to Egypt and Asia. At this period its military power was immense, without its efforts being in the same proportion. These forces were kept up by its riches; it no longer resembled the ancient republics, nor itself as it had been; it stands alone.

Just as peculiar in their way are the wars of Alexander. With a small army, but distinguished for its intrinsic perfection, he overthrew the decayed fabric of the Asiatic states; without rest, and regardless of risks, he traverses the breadth of Asia, and penetrates into India. No republics could do this. Only a king, in a certain measure his own condottiere, could get through so much so quickly.

The great and small monarchies of the Middle Ages carried on their wars with feudal levies. Everything was then restricted to a short period of time; whatever could not be done in that time was held to be impracticable. The feudal force itself was raised through an organisation of vassaldom; the bond which held it together was partly legal obligation, partly a voluntary contract; the whole formed a real confederation. The armament and tactics were based on the right of might, on single combat, and therefore little suited to large bodies. In fact, at no period has the union of states been so weak, and the individual citizen so independent. All this influenced the character of the wars at that period in the most distinct manner. They were comparatively rapidly carried out, there was little time spent idly in camps, but the object was generally only punishing, not subduing the enemy. They carried off his cattle, burnt his towns, and then returned home again.

The great commercial towns and small republics brought forward the condottieri. That was as an expensive, and therefore, as far as visible strength, a very limited military force; as for its intensive strength, it was of still less value in that respect; so far from their showing anything like extreme energy or impetuosity in the field, their combats were generally only sham-fights. In a word, hatred and enmity no longer roused a state to personal activity, but had become articles of trade; war lost a great part of its danger, altered completely its nature, and nothing we can say of the character it then assumed would be applicable to it in its reality.

The feudal system condensed itself by degrees into a decided territorial supremacy; the ties binding the state together became closer; obligations which concerned the person were made the subject of composition; by degrees gold became the substitute in most cases, and the feudal levies were turned into mercenaries. The condottieri formed the connecting-link in the change, and were therefore, for a