This subject has acquired much greater importance in modern warfare from two causes in particular. First, because the armies in general are now much greater than those of the middle ages, and even those of the old world; for, although formerly armies did appear here and there which equalled or even surpassed modern ones in size, still these were only rare and transient occurrences, whilst in modern military history, since the time of Louis XIV, armies have always been very strong in number. But the second cause is still more important, and belongs entirely to modern times. It is the very much closer inner connection which our wars have in themselves, the constant state of readiness for battle of the belligerents engaged in carrying them on. Almost all old wars consist of single unconnected enterprises, which are separated from each other by intervals during which the war in reality either completely rested, and only still existed in a political sense, or when the armies at least had removed so far from each other that each, without any care about the army opposite, only occupied itself with its own wants.
Modern wars, that is, the wars which have taken place since the Peace of Westphalia, have, through the efforts of respective governments, taken a more systematic connected form; the military object, in general, predominates everywhere, and demands also that arrangements for subsistence shall be on an adequate scale. Certainly there were long periods of inaction in the wars of the seventeenth and eighteenth centuries, almost amounting to a cessation of war; these are the regular periods passed in cantonments; still even those periods were subordinate to the military object; they were caused by the inclemency of the season, not by any necessity arising out of the subsistence of the troops, and as they regularly terminated with the return of summer, therefore we may say at all events uninterrupted action was the rule of war during the fine season of the year.