To understand the battle of Waterloo it is necessary, more perhaps than in the case of any other great decisive action, to read it strategically: that is, to regard the final struggle of Sunday the 18th of June as only the climax of certain general movements, the first phase of which was the concentration of the French Army of the North, and the second the passage of the Sambre river and the attack. This second phase covered four days in time, and in space an advance of nearly forty miles.

There is a sense, of course, in which it is true of every battle that its result is closely connected with the strategy which led up to its tactical features: how the opposing forces arrived upon the field, in what condition, and in what disposition and at what time, with what advantage or disadvantage, is always necessarily connected with the history of the campaign rather than of the individual action; but, as we saw in the case of Blenheim, and as might be exemplified from a hundred other cases, the greater part of battles can be understood by following the tactical dispositions upon the field. They are won or lost, in the main, according to those dispositions.

With Waterloo it was not so. Waterloo was lost by Napoleon, won by the Allies, not mainly on account of tactical movements upon the field itself, but mainly on account of what had happened in the course of the advance of the French army to that field. In other words, the military character of that great decisive action is always missed by those who have read it isolated from the movements immediately preceding it.

Napoleon, determining to strike at Belgium under the political circumstances we have already seen, was attacking forces about double his own.

He was like one man coming up rapidly and almost unexpectedly to attack two: but hoping if possible to deal successively and singly with either opponent.

His doubtful chance of success in such a hazard obviously lay in his being able to attack each enemy separately: that is, to engage first one before the second came to his aid; then the second; and thus to defeat each in turn. The chance of victory under such circumstances is slight. It presupposes the surprise of the two allied adversaries by their single opponent, and the defeat of one so quickly that the other cannot come to his aid till all is over. But no other avenue of victory is open to a man fighting enemies of double his numerical strength; at least under conditions where armament, material, and racial type are much the same upon either side.

The possibility of dealing thus with his enemy Napoleon thought possible, and thought it possible from two factors in the situation before him.

The first factor was that the allied army, seeing its great numbers, the comparatively small accumulation of supplies which it could yet command, the great length of frontier which it had to watch, was spread out in a great number of cantonments, the whole stretch of which was no less than one hundred miles in length, from LiÈge upon the east or left to Tournay upon the west or right.

The second factor which gave Napoleon his chance was that this long line depended for its supply, its orders, its line of retreat upon two separate and opposite bases.The left or eastern half, formed mainly of Prussian subjects, and acting under Blucher, had arrived from the east, looked for safety in case of defeat to a retreat towards the Rhine, obtained its supplies from that direction, and in general was fed from the east along those communications, continual activity along which are as necessary to the life of an army as the uninterrupted working of the air-tube is necessary to the life of a diver.

The western or right-hand part of the line, Dutch, German, Belgian, and British, acting under Wellington, depended, upon the contrary, upon the North Sea, and upon communication across that sea with England. That is, it drew its supplies and the necessaries of its existence from the west, the opposite and contrary direction from that to which the Prussian half of the Allies were looking for theirs. The effect of this upon the campaign is at once simple to perceive and of capital importance in Napoleon’s plan.

Wellington and Blucher did not, under the circumstances, oppose to Napoleon a single body drawing its life from one stream of communications. They did not in combination command a force defending one goal; they commanded two forces defending two goals. The thorough defeat of one would throw it back away from the other if the attack were delivered at the point where the two just joined hands; and the English[1] or western half under Wellington was bound to movements actually contrary to the Prussian or eastern half under Blucher in case either were defeated before the other could come to its aid.

Napoleon, then, in his rapid advance upon Belgium, was a man conducting a column against a line. He was conducting that column against one special point, the point of junction between two disparate halves of an opposing line. He advanced therefore upon a narrow front perpendicular to, and aimed at the centre of, the long scattered cordon of his double enemy, which cordon it was his business if possible to divide just where the western end of one half touched the eastern end of the other. He designed to fight in detail the first portion he could engage, then to turn upon the other, and thus to defeat both singly and in turn.I will put this strategical position before the reader in the shape of an English parallel in order to make it the plainer, and I will then, by the aid of sketch maps, show how the Allies actually lay upon the Belgian frontier at the moment when Napoleon delivered his attack upon it.

Imagine near a quarter million of men spread out in a line of separate cantonments from Windsor at one extremity to Bristol at the other; and suppose that the eastern half of this line from Windsor to as far west as Wallingford is depending for its supplies and its communications upon the river Thames and its road system, and is prepared in case of defeat to fall back, down the valley of that stream towards London.

On the other hand, imagine that the western half from Swindon to Bristol is receiving its supplies from the Severn and the Bristol Channel, and must in case of defeat fall back westward upon that line.

Now, suppose an invading column rather more than 120,000 strong to be advancing from the south against this line, but prepared to strike up from almost any point on the Channel. It strikes, as a fact, from Southampton, and marches rapidly north by Winchester and Newbury. By the time it has reached Newbury, the eastern half of the opposing line, that between Wallingford and Windsor, has concentrated to meet it, but is defeated in the neighbourhood of that town.

Such a battle at Newbury would correspond to the battle at Ligny (let it be fought upon a Friday). Meanwhile, the western half, hurrying up in aid, has failed to effect a junction before the eastern half was defeated, comes up too late above Newbury, and finding it is too late, retires upon Abingdon. The victorious invader pursues them, and at noon on the second day engages them in a long line which they hold in front of Abingdon.

If he has only to deal in front of Abingdon with this second or western half, which hurried up too late to help the defeated eastern half, he has very fair chances of success. He is slightly superior numerically; he has, upon the whole, better troops and he has more guns. But the eastern half of the defending army, which has been beaten at Newbury, though beaten, was neither destroyed nor dispersed, nor thrust very far back from the line of operations. It has retreated to Wallingford, that is towards the north, parallel to the retreat of the western half; and a few hours after this western half is engaged in battle with the invader in front of Abingdon, the eastern half appears upon that invader’s right flank, joins forces with the line of the defenders at Abingdon, and thus brings not only a crushing superiority of numbers upon the field against the invader, but also brings it up in such a manner that he is compelled to fight upon two fronts at once. He is, of course, destroyed by such a combination, and his army routed and dispersed. An action of this sort fought at Abingdon would correspond to the action which was fought upon the field of Waterloo, supposing, of course, for the purpose of this rough parallel, an open countryside without the obstacle of the river.

The actual positions of the two combined commands, the command of Blucher and the command of Wellington, which between them held the long line between Tournay and LiÈge, will be grasped from the sketch map upon the next page.

The reader who would grasp the campaign in the short compass of such an essay as this had best consider the numbers and the positions in a form not too detailed, and busy himself with a picture which, though accurate, shall be general.

Let him, then, consider the whole line between LiÈge and Tournay to consist of the two halves already presented: a western half, which we will call the Duke of Wellington’s, and an eastern half, which we will call Blucher’s: of these two the Duke of Wellington was Commander-in-chief.

Next, note the numbers of each and their disposition. The mixed force under the Duke of Wellington was somewhat over 100,000 men, with just over 200 guns.[2] They consisted in two corps and a reserve. The first corps was under the Prince of Orange, and was mainly composed of men from the Netherlands. Its headquarters were at Braine le Comte. The second corps was under Lord Hill, and contained the mass of the British troops present. Its headquarters were at Ath. These two between them amounted to about half of Wellington’s command, and we find them scattered in cantonments at Oudenarde, at Ath, at Enghien, at Soignies, at Nivelles, at Roeulx, at Braine le Comte, at Hal. A reserve corps under the Duke’s own command was stationed at Brussels, and amounted to more than one-fifth, but less than one-quarter, of the whole force. The remaining quarter and a little more is accounted for by scattered cavalry (mainly in posts upon the river Dender), by the learned arms, gunners and sappers, distributed throughout the army, and by troops which were occupying garrisons—in numbers amounting to rather more than ten per cent. of the force.

The eastern Prussian or left half of the line was, as is apparent in the preceding map, somewhat larger. It had a quarter more men and half as many guns again as that under the Duke of Wellington, and it was organised into four army corps, whose headquarters were respectively Charleroi, Namur, Ciney, and LiÈge.

The whole line, therefore, which was waiting the advance of Napoleon, was not quite two and a third hundred thousand men, with rather more than 500 guns. Of this grand total of the two halves, Wellington’s and Blucher’s combined, about eighteen per cent. came from the British Islands, and of that eighteen per cent., again, a very large proportion—exactly how large it is impossible to determine—were Irish.

Now let us turn to the army which Napoleon was leading against this line of Wellington and Blucher. It was just under one hundred and a quarter thousand men strong, that is, just over half the total number of its opponents. It had, however, a heavier proportion of guns, which were two-thirds as numerous as those it had to meet.

This “Army of the North” was organised in seven great bodies, unequal in size, but each a unit averaging seventeen odd thousand men. These seven great bodies were the 1st, 2nd, 3rd, 4th Army Corps, the 6th Army Corps, the Imperial Guard, and the reserve cavalry under Grouchy.

The concentration of this army began, as I said in a previous section, upon the 5th of June, and was effected with a rapidity and order which are rightly regarded as a model by all writers upon military science.

The French troops, when the order for concentration was given, stretched westward as far as Lille, eastward as far as Metz, southward as far as Paris, in the neighbourhood of which town was the Imperial Guard. The actual marching of the various units occupied a week. Napoleon was at the front on the night of the 13th of June; the whole army was upon the 14th drawn up upon a line stretched from Maubeuge to Philippeville, and the attack was ready to begin.

The concentration had been effected with singular secrecy, as well as with the promptitude and accuracy we have noted; and though the common opinion of Wellington and Blucher, that Napoleon had no intention of attacking, reposed upon sound general judgment—for the hazard Napoleon was playing in this game of one against two was extreme,—nevertheless it is remarkable that both of these great commanders should have been so singularly ignorant of the impending blow. Napoleon himself was actually over the frontier at the moment when Wellington was writing at his ease that he intended to take the offensive at the end of the month, and Blucher, a few days earlier, had expressed the opinion that he might be kept inactive for a whole year, since Bonaparte had no intention of attacking.

By the evening of Wednesday, June the 14th, all was ready for the advance, which was ordered for the next morning.

It would but confuse the general reader to attempt to carry with him through this short account the name and character of each commander, but it is essential to remember one at least—the name of Erlon; and he should also remember that the corps which Erlon commanded was the First Corps; for, as we shall see, upon Erlon’s wanderings with this First Corps depended the unsatisfactory termination of Ligny, and the subsequent intervention of the Prussians at Waterloo, which decided that action.

It is also of little moment for the purpose of this to retain the names of the places which were the headquarters of each of these corps before the advance began. It is alone important to the reader that he should have a clear picture of the order in which this advance took place, for thus only will he understand both where it struck, and why, with all its rapidity, it suffered from certain shocks or jerks.

Napoleon’s advance was upon three parallel lines and in three main bodies.

The left or westernmost consisted of the First and Second Corps d’ArmÉe; the centre, of the Imperial Guard, together with the Third and Sixth Corps. The third or right consisted of the Fourth Corps alone, with a division of cavalry. These three bodies, when the night of Wednesday the 14th of June fell, lay, the first at Sorle and Leer; the second at Beaumont, and upon the road that runs through it to Charleroi; the third at Philippeville.

It is at this stage advisable to consider why Napoleon had chosen the crossing of the Sambre at Charleroi and the sites immediately to the north on the left bank of that river as the point where he would strike at the long line of the Allies.

Many considerations converged to impose this line of advance upon Napoleon. In the first place, it was his task to cut the line of the Allies in two at the point where the extremity of one army, the Prussian, touched upon the extremity of the other, that of the Duke of Wellington. This point lay due north of the river-crossing he had chosen.

Again, the main road to Brussels was barred by the fortress of Mons, which, though not formidable, had been put in some sort of state of defence.

Again, as a glance at the accompanying map will show, the Prussian half of the allied line was drawn somewhat in front of the other half; and if Napoleon were to attack the enemy in detail, he must strike at the Prussians first. Finally, the line Maubeuge-Philippeville, upon which he concentrated his front, was, upon the whole, the most central position in the long line of his frontier troops, which stretched from Metz to the neighbourhood of the Straits of Dover. Being the most central point, not only with regard to these two extremities, but also with regard to distant Paris, it was the point upon which his concentration could most rapidly be effected.

This, then, was the position upon the night of the 14th. The three great bodies of French troops (much the largest of which was that in the centre) to march at dawn, the light cavalry moving as early as half past two, ahead of the centre, the whole body of which was to march on Charleroi.

The left, that is the First and Second Corps, to cross the Sambre at Thuin, the Abbaye d’Aulne, and Marchiennes. (There were bridges at all three places.) The right or Fourth Corps was also to march on Charleroi.[3]

Napoleon intended to be over the river with all his men by the afternoon of the 15th, but, as we shall see, this “bunching” of fully half the advance upon one crossing place caused, not a fatal, but a prejudicial delay. Among other elements in this false calculation was an apparent error on the part of Soult, who blundered in some way which kept the Third Corps with the centre instead of relieving the pressure by sending it over with the Fourth to cross, under the revised instructions, by ChÂtelet.

Disposition of the Four Prussian Corps on June 15th, 1815.

At dawn, then, the whole front of the French army was moving. It was the dawn of Thursday the 15th of June. By sunset of Sunday all was to be decided.

At this point it is essential to grasp the general scheme of the operations which are about to follow.

Put in its simplest elements and graphically, the whole business began in some such form as is presented in the accompanying sketch map.