Cavalry is a terrible weapon in the hands of one who knows how to use it. Who can say that Epaminondas could have defeated the Spartans twice without his Thessalonian cavalry.
Eventually rifle and artillery fire deafen the soldier; fatigue overpowers him; he becomes inert; he hears commands no longer. If cavalry unexpectedly appears, he is lost. Cavalry conquers merely by its appearance. (Bismarck or Decker).
Modern cavalry, like ancient cavalry, has a real effect only on troops already broken, on infantry engaged with infantry, on cavalry disorganized by artillery fire or by a frontal demonstration. But against such troops its action is decisive. In such cases its action is certain and gives enormous results. You might fight all day and lose ten thousand men, the enemy might lose as many, but if your cavalry pursues him, it will take thirty thousand prisoners. Its role is less knightly than its reputation and appearance, less so than the rôle of infantry. It always loses much less than infantry. Its greatest effect is the effect of surprise, and it is thereby that it gets such astonishing results.
What formation should infantry, armed with modern weapons, take to guard against flank attacks by cavalry? If one fires four times as fast, if the fire is better sustained, one needs only a quarter as many men to guard a point against cavalry. Protection might be secured by using small groups, placed the range of a rifle shot apart and flanking each other, left on the flank of the advance. But they must be dependable troops, who will not be worried by what goes on behind them.
4. Armor and Armament
An armored cavalry is clearly required for moral reasons.
Note this with reference to the influence of cuirassiers (armored cavalrymen) on morale. At the battle of Renty, in 1554, Tavannes, a marshal, had with him his company armored in steel. It was the first time that such armor had been seen. Supported by some hundreds of fugitives who had rallied, he threw himself at the head of his company, on a column of two thousand German cavalry who had just thrown both infantry and cavalry into disorder. He chose his time so well that he broke and carried away these two thousand Germans, who fell back and broke the twelve hundred light horsemen who were supporting them. There followed a general flight, and the battle was won.
General Renard says "The decadence of cavalry caused the disappearance of their square formations in battle, which were characteristic in the seventeenth century." It was not the decadence of the cavalry but the abandonment of the cuirass and the perfecting of the infantry weapon to give more rapid fire. When cuirassiers break through they serve as examples, and emulation extends to others, who another time try to break through as they did.
Why cuirassiers? Because they alone, in all history, have charged and do charge to the end.
To charge to the end the cuirassiers need only half the courage of the dragoons, as their armor raises their morale one half. But since the cuirassiers have as much natural courage as the dragoons, for they are all the same men, it is proper to count the more on their action. Shall we have only one kind of cavalry? Which? If all our cavalry could wear the cuirass and at the same time do the fatiguing work of light cavalry, if all our horses could in addition carry the cuirass through such work, I say that there should be only cuirassiers. But I do not understand why the morale given by the cuirass should be lightly done away with, merely to have one cavalry without the cuirass.