Napoleon spent the early morning in closing up his army, and writing what proved to be the most important letter of the cam paign to Ney (Charleroi, about 8 A.m.) : "I have adopted as the general principle for this campaign to divide my army into two wings and a reserve. . . . The Guard will form the reserve, and I shall bring it into action on either wing just as circumstances dictate. . . . According to circumstances I shall weaken one wing to strengthen my reserve. . . ." Here, in its simplest form, is the principle that underlies Napoleon's strategy in 1815. Only on the wing on which the reserve is brought into action will a decisive result be aimed at. The other is to be used exclusively to neutralize the other enemy, by holding him at bay.
Napoleon's plan for this day assumed that the surprised allies would not risk a forward concentration. The emperor intended to push an advanced guard to Gembloux to ward off BlUcher, and move up the Guard to Fleurus. But once in possession of Som breffe, the emperor would swing the reserve westward to join Ney, who should then have mastered Quatre Bras and have pushed out a force to link with Grouchy, as well as another body 6 m. to the northward. The centre and left wing would then march by night to Brussels. The allies would thus be irremediably sundered. Meanwhile Napoleon and the VI. Corps waited at Charleroi for further information. Up till noon Ney took no serious step to capture Quatre Bras, which still lay at his mercy. Grouchy reported that Prussian masses were coming up from Namur, but Napoleon ignored this. Before io A.M. Ney reported considerable hostile forces at Quatre Bras. The marshal was ordered to crush what was in front of him and report to Fleurus. Here Napoleon arrived at i i A.M., still leaving Lobau at Charleroi. Napoleon at once reconnoitred the situation. Only one Prussian corps was showing, but it was disposed parallel to the Namur road, as if to cover a forward concentration. Had the decisive day arrived? If so, by 2 P.M. Vandamme, Gerard, Pajol and Exelmans would be available for the assault, and the Guard and Milhaud would act as a reserve. At 2 P.M. Napoleon ordered Ney to secure Quatre Bras, as the emperor was attacking the Prussian corps. Whichever wing succeeded first would then wheel inwards and help the other. The decisive flank had not yet be come clear.
Blucher had determined to fight. Wellington, on arrival at Quatre Bras, finding all was quiet, rode over to meet Blucher at Brye. Considering no serious force was in front of Quatre Bras, Wellington ended the interview with the conditional promise that he would bring his army to Blucher's assistance at Ligny, if he was not attacked himself. But on his return to Quatre Bras he found the situation already critical.
he advanced, though the Prince of Orange had only 7,500 troops at Quatre Bras. The Prince had boldly scattered his force, made wise use of cover and showed a firm front to Ney. It was 2 P.M. when the French attacked. East of the road the Dutch-Belgians were forced back and the line wavered. But at 3 P.M. Merlen's cavalry rode in from Nivelles, Picton and the 5th division marched up from Brussels, and Wellington himself returned. Picton stopped the French advance, but Reille's last division was thrown in on the French left, and a hot fight broke out. The Brunswick con tingent now reached Wellington and at once attacked. It was P.M. Ney had just received Napoleon's 2 P.M. order, and he promptly pressed his attack and almost cleared the Bossu wood. However, at 5 P.M. Alten's division arrived from Nivelles, and Ney realized that he needed D'Erlon's corps to gain the cross-roads.
About 5:15 P.M. Ney learned that D'Erlon, without his knowl edge, had moved eastwards .to co-operate at Ligny. Then at 5 :3o P.M. he received Napoleon's order to seize Quatre Bras and swing in against Blucher who was pinned at Ligny. Napoleon added, "the fate of France is in your hands." Ney's duty was clear. He must hold Wellington at Quatre Bras and allow D'Erlon to ensure that a decisive success was gained that day at Ligny. In no case could D'Erlon return in time to be of any use at Quatre Bras. Ney, beside himself with rage, sent imperative orders to D'Erlon to return and ordered Kellermann's cuirassier brigade to break through Wellington's line. The charge was admirably executed. A British regiment, caught in line, was overthrown and lost a colour. But unsupported, the horsemen were then beaten back. At that moment Ney received a verbal message from Napoleon ordering him, whatever happened at Quatre Bras, to allow D'Erlon to carry out the move to Ligny. Despite remonstrance, Ney refused to reconsider D'Erlon's recall and plunged into the fight. Then about 7 P.M. the British Guards reached Wellington and at last gave him the numerical superiority. Promptly the duke attacked all along the line, and by nightfall the French had been driven back to Frasnes. The losses were, Anglo-Dutch 4,70o, French 4,300. At 9 P.M., when the battle was over, D'Erlon arrived. The corps had reached the edge of the Ligny battlefield when it received the counter-order. Thinking he was still under Ney, D'Erlon decided to leave one division at Wagnelee and to return to the left wing. The incident was immeasurably unf or tunate for the French. Had D'Erlon been used betimes at Quatre Bras, Wellington would have been crushed; had he only engaged at Ligny, D'Erlon would have ensured Blucher's annihilation. But oscillating between the two fields the Corps took part in neither. At 10 P.M. Ney wrote a short and somewhat one-sided report to Soult.