Allied strategy in the Battle of Waterloo

Unlike the French army, which was under the ultimate control and command of Napoleon, and which had been raised in and was situated within France, the coalition forces that made up the allied armies were scattered.

In the case of the Austrians, part of their forces were fighting elsewhere, in Italy. The larger Austrian force had therefore to remain within a reasonable distance to ensure they could support their army fighting Murat in Italy. The Russian army made a slow progress across the vast expanse of Central Europe: in May it was still in Russia and Poland. How then were the allied troops which were within striking distance of France — the Anglo-Allied army commanded by Wellington containing British, Hanoverian, Dutch and Belgian troops with contingents from Brunswick and Nassau and the Prussian forces under Blücher — to be disposed?

Gathering the allied forces
The allied force that Wellington was due to command was gathering in the Low Countries: the obvious location to canton these forces was close to the north-eastern borders of France — a strike by Napoleon against the Low Countries was the most likely scenario for French aggression; parts of Belgium, and Belgian forces, would be sympathetic to France; and it would break up one of the creations of the peace of 1814, the Low Countries. Besides, it was to the Low Countries that Louis XVIII had fled. The allies had always considered the Low Countries vulnerable and a substantial investment was to be made in fortifications to protect the new country against the French. Wellington had inspected the defences when he had travelled that way in 1814 en route to take up the Paris embassy — and he had even visited Waterloo that summer, presumably reconnoitring it as a potential defensive battlefield.

The best position for the forces?
When Wellington arrived in Brussels on 4 April to take command of the forces he found that discussions were already underway about combining the Anglo-Allied and Prussian armies against the French. The Prussians favoured a position centred on Tirlemont, east of Brussels. Wellington, however, felt that it was absolutely imperative for political reasons to avoid the possibility of Napoleon occupying Brussels and therefore suggested a position south of the city. Count von Gneisenau, who temporarily commanded the Prussians whilst they awaited the arrival of Field Marshal Blücher, agreed and the forces were mobilised.

By May, the Anglo-Allied force under the command of the Duke of Wellington and the Prussian army of the Lower Rhine, commanded by Field Marshal Blücher, were cantoned along a front of around 150 miles in length from Ostend to Liège and down to Dinant in the Ardennes. General von Kleist commanded a Prussian corps based near Blücher, watching the French fortress of Sedan. The two commanders maintained their own headquarters: to ensure co-ordination and facilitate communication, a liaison officer was attached to each. General Müffling with Wellington, and Lieutenant Colonel Sir Henry Hardinge with Blücher.

What were the lines of communication?
The disposition of the troops had to allow lines of communication to be maintained — Wellington’s with England, by way of Ghent, Bruges and Ostend, Blücher with Berlin through Namur and Liege — and to enable them to deal with the possibility of attack by the French before the other allied forces arrived. Wellington did not feel that an offensive action was feasible without other allied forces and hence his best option was to establish as strong a defensive position as possible. To help the forces maintain their defensive positions, Wellington had, immediately on his arrival at Brussels, begun work on repairing the defences of the ports and the chain of fortresses along the border of the Low Countries. These fortresses offered the main protection on a border that was mostly open landscape, with only a small proportion protected by rivers. The ports were essential for British communications and also for supplies, and were a vital part of the strategy for maintaining the forces. William I, King of the Netherlands, however, viewed Wellington’s concern with the state of Ostend and Antwerp with suspicion, fearing that the British were more concerned with providing an escape route for their army should the Low Countries be overrun.

Practical considerations
The cantonment of forces (their lodgings and disposition while waiting) owed something to practical considerations as well as strategy. Horse regiments — cavalry and horse artillery — required supplies of fresh grass or hay: those of Wellington’s army were scattered around the villages to the west of Brussels where there were ample meadows and pasture. There they were able to lodge with the local population and purchase supplies from them. The Prussian army was similarly spread over a large area to minimise the burden on the local population.

Weaknesses in the allied strategy
The main weakness of this disposition of the forces overall was that it would take time to concentrate them as a united force. The outlying flanks were exposed: a lightly garrisoned flank might be identified by Napoleon as a weak point for attack — his strategy must be to divide allied forces and to fight them individually before they could combine.

Document: a private letter from Wellington to Lieutenant General Sir Charles William Stewart
On 8 May, Wellington sent this letter from Brussels to Lord Stewart, who was one of the plenipotentiaries at the Congress of Vienna, and discussed his strategy for the disposition of the forces and how this might answer a possible attack by the French, the strength of the French and the different classes of force they had. Wellington has information from two French sources — Clarke (the Duc de Feltre) who had been Minister of War under Napoleon and under Louis XVIII, and had gone into exile with him — and Beurnonville, another French general, who had also gone into exile with Louis XVIII. The allies were very concerned to establish reliably the size of the force that Bonaparte could put in the field.

My Dear Charles

I have received your letters of the 28th April, for which I am very much obliged to you — and I have perused with the greatest attention the memorandum which you enclosed.

I saw Clarke yesterday, and he told me that a person of the War Office upon whom he could depend, had informed him that on the 30th April the enemy’s regular army consisted of 139,000 men; and the Guards to 25,000 — gendarmerie, and national guards raised and expected to be raised would make it 280,000. This was the utmost expected.

Beurnonville, who ought to know told me this day, that we ought to reckon that the enemy had an effective force of 200,000 men. He says the King had 155,000 when he quitted Paris, and that he had granted above 100,000 congés [leaves of absence], which had been called in — but that not above half could be reckoned upon as likely to join. I understand likewise that there were above 100,000 deserters wandering about France.

In reference to these different statements, I beg you to observe that Clarke speaks from positive information; Beurnonville from conjecture. According to Clarke’s account the army gained in strength only 3000 men in the last fifteen days; but then it must be observed that the guards have gained about 19,000, being the difference between 6,000, which they were, and 25,000 which they are now.

In respect to periods of commencing operations, you will have seen that I had adopted the opinion that it was necessary to wait for more troops, as far back as the 13th of April. After, however, that we shall have waited a sufficient time to collect a force, and to satisfy military men that their force is what it ought to be to enable them to accomplish the object in view; the period of attack becomes a political question, upon which there can be no difference of opinion. Every day’s experience convinces me that we ought not to lose a moment which could be spared.

I say nothing about our defensive operations, because I am inclined to believe that Blücher and I are so well united, and so strong that the enemy cannot do us much mischief. I am at the advanced post of the whole; the greatest part of the enemy’s force is in my front; and if I am satisfied, others need be under no apprehension. In regard to offensive operations; my opinion is that however strong we shall be in reference to the enemy, we should not extend ourselves further than is absolutely necessary in order to facilitate the subsistence of the troops. I don’t approve of an extension from the Channel to the Alps; and I am convinced it will be found not fatal, but that the troops at such a distance on the left of our line, will be entirely out of the line of the operations.

We are now, or shall be shortly placed on the French frontier in the form of an echelon, of which the right placed here is the most advanced of the echelons, and the left upon the Upper Rhine is the most retired.

Paris is our object, and the greatest force, and greatest military difficulties are opposed to the movements of the right, which is the most advanced part of our general line. Indeed such force and difficulties are opposed to us in this part, that I should think that Blücher and I cannot move till the movements of others of the allied corps will have relieved us from part of the enemy’s force opposed to us. Then it must be observed that we cannot be relieved by movements through Luxembourg.

In my opinion then, the movement of the allies should begin with the left, which should cross the Rhine between Basle and Strasbourg.The centre collected upon the Sarre should cross the Meuse on the day the left should be expected to be at Langrès.

If these movements should not relieve the right, they should be continued; that is to say, the left should continue its movement on both banks of the Marne, while the centre should cross the Aisne and the distance between the two bodies, and between each and Paris should be shortened daily.

But this last hypothesis is not probable; the enemy would certainly move from this front upon the earliest alarm of the movements on the Upper Rhine; and the moment he did move, or that the operation should be practicable; Blücher’s corps and mine should move forward, and the former make the siege of Givet, the latter of Maubeuge; and the former likewise to aid the movement of the centre across the Meuse.

If the enemy should fall upon the centre, it should either retire upon Luxembourg, or fight according to the relative strength; and in either case Blücher should act upon the enemy’s communication upon the Aisne.

But the most probable result of these first movements, would be the concentration of the enemy’s forces upon the Aisne; and accordingly we hear of the fortifications of Soissons and Laon; of an intrenched camp at Beauvais, etc., etc. We must in this case after the first operation, throw our whole left across the Marne, and strengthen it if necessary from the centre, and let it march upon Paris, between the Seine and the Marne; while the right and the centre should either attack the enemy’s position upon the Aisne, or endeavour to turn its left; or the whole should cooperate in one general attack upon the enemy’s position.

I come now to consider the strength required for these operations. The greatest strength the enemy is supposed to have is 200,000 effective men, besides national guards for his garrisons. Of this number it can hardly be believed that he can bring 150,000 to bear upon any one point.

Upon this statement let our proceedings be founded. Let us have 150,000 men upon the left; and 150,000 men upon the right; and all the rest, whatever they may be in the centre; or after a sufficient centre is formed let the remainder be in reserve for the right, left, or centre, as may be most convenient for their march and subsistence, and I’ll engage for the result, as they may be thrown where we please. Let us begin, when we shall have 450,000 men. Before the Austrians upon the left shall be at Langrès, the Russians will have passed the Rhine; and the whole Prussian army will be in line.

These are my general ideas, which I don’t think differ much from Kniesbeck’s. Mind when I think of the siege of Givet and Maubeuge, I don’t mean by the whole of the two armies of the right, but to be carried on by detachments from them. The centre should seize Sedan, which is not strong or garrisoned, and observe Longvy, Thionville and Metz. The left will have to observe Hunningen and the fortresses in Alsace.

In regard to the force in Piedmont I confess that I wish that the whole Austrian army in Italy was actively employed against Murat, with the exception of the garrisons. Murat must be destroyed early, or he will hang heavily upon us. If any force should be employed from Piedmont, its operations should be separate from those of the great confederacy. They cannot be connected without disconnecting those of what I have hitherto considered the left from the remainder of our great line; however, they may be calculated to aid that left particularly by being directed upon Chambéry, or by keeping that post in check. Their basis is, however different; and cannot easily be made otherwise.

These opinions are for yourself; God knows whether they can be acted upon, or whether the allies will allow their forces to be divided as I suppose; and particularly whether the Prussians will act in two corps, one under Blücher here, and another from Luxembourg with the centre; or whether the other allies will like to commence till the whole Russian army is en mesure. But I am convinced that what I have proposed is so clearly the plan of operations, that I don’t doubt it will be adopted, with but little variation.

[University of Southampton Library, MS 61 Wellington Papers 1/464/42. Crown copyright: reproduced by permission of Her Majesty’s Stationery Office]