Upon a calculation being made, however, of the time which would elapse ere the Duke would be able to collect the requisite force for undertaking this operation, and of the possibility of Blücher being defeated before it could be carried into effect, it was considered preferable that Wellington should, if practicable, move to the support of the Prussian Right by the Namur road. But a direct support of this kind was necessarily contingent on circumstances, and subject to the Duke's discretion. The latter having expressed his confident expectation of being enabled to afford the desired support, as also of his succeeding in concentrating, very shortly, a sufficient force to assume the offensive, rode back to Quatre Bras.

It was nearly eleven o'clock when General Flahaut, an Aide de Camp of the Emperor, after passing through Gosselies, arrived at Frasne, with the following letter from the latter to the Marshal:

"Au Maréchal Ney. "To Marshal Ney.
"Mon Cousin—Je vous envoie; mon Aide de Camp, le Général Flahaut, qui vous porte la présente lettre. Le Major Général a dû vous donner des Ordres; mais vous recevrez les miens plus tôt, parceque mes Officiers vont plus vite que les siens. Vous recevrez l'Ordre du Mouvement du Jour; mais je veux vous en écrire en détail, parceque c'est de la plus haute importance. My Cousin—I send you my Aide de Camp, General Flahaut; who brings you the present letter The Major General [Soult] will give you the Orders; but you will receive mine sooner, because my Officers go quicker than his. You will receive the Order of Movement of the Day: but I wish to write to you respecting it in detail, because it is of the highest importance.
"Je porte le Maréchal Grouchy avec les 3e et 4e Corps d'infanterie sur Sombref. Je porte ma Garde à Fleurus, et j'y serai de ma personne avant midi. J'y attaquerai l'Ennemi si je le rencontre, et j'éclairerai la route jusqu'à Gembloux. La d'après ce qui ce passera, je prendrai mon parti peutêtre à trois heures après midi, peutêtre ce soir. Mon intention est que, immédiatement après que j'aurai pris mon parti, vous soyez prêt à marcher sur Bruxelles, je vous appuierai avec la Garde qui sera à Fleurus ou à Sombref, et je désirerais arriver à Bruxelles demain matin. Vous vous mettriez en marche ce soir même si je prends mon parti d'assez bonne heure pour que vous puissiez en être informé de jour et faire ce soir trois ou quatre lieues et être demain à sept heures du matin à Bruxelles. "I direct Marshal Grouchy with the Third and Fourth Corps of Infantry on Sombref. I direct my Guard to Fleurus, and I shall be there personally before noon. I shall attack the Enemy there if I meet with him, and I shall clear the road as far as Gembloux. There, according to what will happen, I shall make my decision; perhaps at three o'clock in the afternoon, perhaps this evening. My intention is that, immediately after I shall have made my decision, you may be ready to march on Brussels. I will support you with the Guard which will be at Fleurus or at Sombref; and I would desire to arrive at Brussels to morrow morning. You would march this evening even if I make my decision at a sufficiently early hour that you may be informed of it in daylight, and traverse this evening three or four leagues, and be at Brussels to morrow at seven o'clock in the morning.
"Vous pouvez donc disposer vos troupes de la manière suivante:— Première Division à deux lieues en avant des Quatre Chemins s'il n'y a pas d'inconvénient. Six Divisions d'infanterie autour des Quatre Chemins, et une Division à Marbais, afin que je puisse l'attirer à moi à Sombref, si j'en vais besoin. Elle ne retarderait d'ailleurs pas votre marche. Le Corps du Comte de Valmy, qui a 3,000 Cuirassiers d'Élite, à l'intersection du chemin des Romains et de celui de Bruxelles, afin que je puisse l'attirer à moi, si j'en avais besoin; aussitot que mon parti sera pris, vous lui enverrez l'Ordre de venir vous rejoindre. Je désirerais avoir avec moi la Division de la Garde que commande le Général Lefèbvre-Desnouettes, et je vous envoie les deux Divisions du Corps du Comte de Valmy pour la remplacer. Mais dans mon projet actuel, je préfère placer le Comte de Valmy de manière à le rappeler si j'en avais besoin, et ne point faire de fausses marches au Général Lefèbvre-Desnouettes; puisqu'il est probable que je me déciderai ce soir à marcher sur Bruxelles avec la Garde. Cependant, couvrez la Division Lefèbvre par les deux Divisions de Cavalrie d'Erlon et de Reille, afin de ménager la Garde; et que, s'il y avait quelque échauffourée avec les Anglais, il est préférable que ce soit sur la Ligne que sur la Garde. "You may then dispose your troops in the following manner:— First Division at two leagues in front of Quatre Bras, if in doing so there is no inconvenience. Six Divisions of Infantry about Quatre Bras; and one Division at Marbais, so that I may draw it to myself at Sombref, if I should have need of it. It would not otherwise retard your march. The Corps of the Count de Valmy, which has 3,000 Cuirassiers d'Élite, at the intersection of the Roman road with that of Brussels, in order that I may draw it to myself if I should have need of it: as soon as my decision is made, you will send him the Order to rejoin you. I would desire to have with me the Division of the Guard commanded by General Lefèbvre Desnouettes, and I send you the two Divisions of the Corps of the Count de Valmy to replace it. But in my present design, I prefer to place the Count de Valmy in such a manner as to be able to recall him if I should have need of him; and not to make false marches for General Lefèbvre Desnouettes: since it is probable that I shall decide this evening to march on Brussels with the Guard. However, cover Lefèbvre's Division with the two Cavalry Divisions of d'Erlon and Reille, in order to spare the Guard; and that, if there shall be any affray there with the English, it may be with the Line rather than with the Guard.
"J'ai adopté comme principe général pendant cette Campagne, de diviser mon Armée en deux Ailes et une Réserve. Votre Aile sera composée des quatre Divisions du 2e Corps, de deux Divisions de Cavalerie Légère, et de deux Divisions du Corps de Valmy. Cela ne doit pas être loin de 45 à 50 mille hommes. I have adopted as a general principle during this Campaign to divide my Army into two Wings and a Reserve. Your Wing will be composed of the four Divisions of the Second Corps, the two Light Cavalry Divisions, and the two Divisions of the Corps de Valmy. That ought not to be far from 45,000 to 50,000 men.
"Le Maréchal Grouchy aura à peu près la même force, et commandera l'Aile Droite. La Garde formera la Réserve, et je me porterai sur l'une ou l'autre Aile, selon les circonstances. Le Major Général donné les Ordres les plus précis pour qu'il n'y ait aucune difficulté sur l'obéissance à vos Ordres lorsque vous serez détaché; les Commandants de Corps devant prendre mes Ordres directement quand je me trouve présent. Selon les circonstances, j'affaiblirai l'une ou l'autre Aile en augmentant ma Réserve. "Marshal Grouchy will have nearly the same force, and will command the Right Wing. The Guard will form the Reserve, and I shall repair to one or other Wing according to circumstances. The Major General is giving the most precise Orders that there may be no difficulty as regards obedience to your Orders when you will be detached; the Commanders of Corps must take my Orders directly from me, when I am present. According to circumstances, I shall weaken the one, or the other, Wing in augmenting my Reserve.
"Vous sentez assez l'importance attachée à la prise de Bruxelles. Cela pourra d'ailleurs donner lieu à des accidents, car un mouvement aussi prompt et aussi brusque isolera l'Armée Anglaise de Mons, Ostende, etc. Je désire que vos dispositions soient bien faites pour qu'au premier Ordre, vos huit Divisions puissent marcher rapidement, et sans obstacle sur Bruxelles."N." "You will sufficiently perceive the importance attached to the capture of Brussels. That will otherwise give occasion to incidents: for a movement equally prompt and abrupt will isolate the English Army from Mons, Ostend, &c. I would desire that your dispositions may be well made that, at the first Order, your eight Divisions may march rapidly and without obstacle upon Brussels."N."
"Charleroi, le 16 Juin, 1815." "Charleroi, 16th June 1815."

This letter, which was intended to convey to Ney a general notion of Napoleon's intentions, prescribed to him, at the same time, as a principle, that he was to consider his movements subordinate to those of the Emperor. The latter intimated his purpose of attacking the Enemy at Fleurus, should he find him there, and of pushing on as far as Gembloux, where he would decide upon his plan of further operation, "perhaps at three o'clock in the afternoon, perhaps in the evening;" immediately after which Ney was to be ready to march upon Brussels, supported by Napoleon with the Guards, it being the Emperor's desire to reach that capital in the morning.

The idea of advancing upon Gembloux, and of capturing Brussels by a coup de main, which could only be effected by a vigorous repulse and signal defeat of the Corps of Zieten, and by a successful turning and partial dispersion of those of Pirch and Thielemann, as also by the rapid march of a closely collected force under Ney, proves that Napoleon had either been insufficiently informed as to the general dispositions of his opponents, or had greatly miscalculated the degree of energy and promptitude required in his movements for the execution of such a design.

Very shortly afterwards, Ney received the official Order of Movement to which Napoleon adverted in his letter as having been sent by Soult. It instructed him to put the Second and First Corps d'Armée, as also the Third Corps of Cavalry which had been placed at his disposal, in movement upon Quatre Bras; to take up a position at that point; thence to push forward reconnaissances as far as possible on the roads to Brussels and Nivelles, d'où probablement l'Ennemi s'est retiré; to establish, should he meet with no impediment, a Division with some Cavalry at Genappe; and to detach another Division towards Marbais, in order to cover the interval between Sombref and Quatre Bras. He was also to desire the General Officers commanding the two Corps d'Armée to assemble their troops, collect the stragglers, and order up all the waggons belonging to the Artillery and to the Hospitals that might still be in the rear.

In pursuance of these instructions, Ney despatched Orders of Movement to Counts Reille and d'Erlon.