and give time for Blücher's concentration, at the same time retaining his own freedom of manœuvre, and this in spite of the great length of the summer day, the short distance that he lay in front of Fleurus, the tremendous numerical superiority of the French and Napoleon's personal presence at their head.
When the French left wing and centre reached the Sambre bridges, at Marchienne and Charleroi, they found them held and strongly barricaded, and the cavalry were powerless to force the passage. It was nearing noon when the emperor reached the front with the Young Guard, whom he had personally hurried forward. He immediately took action, and under his direction the bridge at Charleroi was stormed shortly after noon. Almost at the same time Reille forced the passage at Marchienne. Instead of drawing his corps together and retreating en masse up the Fleurus road, Zieten wisely withdrew on two roads, using those to Quatre Bras and Fleurus. The defenders of Marchienne used the former, while the brigade which had held Charleroi fell back by the latter The emperor at once began the advance along both the roads. The left wing was directed to push up the Gosselies-Quatre Bras road, and Pajol's cavalry followed the Prussians who retired along the Gilly-Fleurus road. The emperor took post at Charleroi About 3 p.m. Marshal Ney joined the army, was given the command of the left wing, and ordered to drive the Prussians out of Gosselies, and clear the road northward of that place. Ney took over his command just when the attack on Gosselies was impending. The Prussians were driven from the town, but they managed to effect a roundabout retreat to Ligny, where they rallied. Ney pushed on his advance up the Brussels road. When he had left for the front, the emperor proceeded with Grouchy to reconnoitre the Prussian position at Gilly, and handing over the command of the right wing to the marshal, whom he ordered to capture Gilly, Napoleon returned to Charleroi, to hasten the passage of the French army across the Sambre and mass it in the gap between the allies. But the head of Vandamme's corps had by this time crossed the river, and the emperor ordered it to assist Grouchy.
What meanwhile were the allies doing? There is no doubt that, surprised by the suddenness of the French advance, they were caught unprepared. But on the 15th the critical nature of the situation dawned on them, and naturally on Blücher first, as his headquarters were nearer to the frontier than Wellington's, and Blücher had had previous experience of Napoleon's powers. As soon as the Prussian marshal got the first real warning of imminent danger, he ordered (in accordance with the prearranged plan) an immediate concentration of his army on his inner flank at Sombreffe. Unfortunately for him the first orders sent to Bülow by Gneisenau, chief of the staff, at midnight June 14-15, were written in so stilted and hazy a style that Bülow did not consider any especial display of energy was required. Hence the IV Corps was neutralized until after the 16th. The other two corps commanders (Pirch I. and Thielemann) received clearer orders, and acted promptly enough. They concentrated their scattered men and hastened to march to the appointed rendezvous. By nightfall Pirch I. had bivouacked the II. Corps at Mazy, only 4 m. short of Sombreffe, and Thielemann and the III. Corps had reached Namur, within easy distance of the Ligny battlefield. Blücher wisely shifted his own headquarters to Sombreffe on the afternoon of the 15th.
Wellington's position at nightfall was very different, and can hardly be termed safe or even satisfactory. Definite news of the French advance only reached Brussels about 3 p.m. on the 15th; and even then the duke was by no means certain of the direction of Napoleon's main stroke. Hence the first orders he issued were for his divisions to concentrate at their respective alarm-posts, intending later to send them further orders when the situation had somewhat cleared up. For whatever reasons, Wellington thought Napoleon would attempt to turn his right and cut his line of communications. Had Napoleon attempted this he would (if successful) have driven the Anglo-Dutch army back upon the Prussians, instead of separating the allies, as he actually tried to do and very nearly succeeded in doing. Failing to appreciate this fully, Wellington omitted to order an immediate concentration on his inner (left) flank as Blücher had done, and the danger of Blücher's position was thus enormously increased.
Curiously enough, the allies do not appear to have decided upon the course to be taken in case they were surprised, as they virtually were, and their system of intercommunication—if system it can be called—was most imperfect. They ought to have arranged loyally and promptly to let each other know every move it was proposed to make and the reasons for moving, for thus only could concerted action be ensured when confronted with Napoleon, “in whose presence it was so little safe to make … a false movement.”
Wellington's subordinates at the critical point, however, acted with admirable boldness. Prince Bernard, in command of a brigade at Quatre Bras and Frasnes, recognizing the pressing danger that threatened on the Brussels road, retained his position there to check the French advance, instead of drawing off westwards and massing with the rest of his division at Nivelles; and in this action he was firmly supported by his immediate superiors. It was due to their presence of mind that Wellington maintained his hold on the important strategical point of Quatre Bras on June 15 and 16. Consequently, as Ney's wing advanced northward from Gosselies along the Brussels road, it came upon an advanced detachment of this force at Frasnes. The detachment was quickly forced to retire on its supports at the cross-roads, but here Prince Bernard firmly held his position; and by his skilful use of cover and the high standing corn he prevented the French gauging the weakness of the small force that barred their way. The day was now drawing to a close, and Ney decided wisely not to push his advance any farther. He was in front of a force of unknown strength which appeared resolved to stand its ground, his men were tired, and the cannon-thunder to his right rear proclaimed clearly that Grouchy had not made much headway on the Fleurus road. To push on farther might isolate the left wing among a host of allies. He therefore halted his command, and, later, made a report to the emperor.
Meanwhile two long hours had been wasted on the right whilst Grouchy and Vandamme deliberated over their plan of action in front of the Prussian brigade at Gilly, and it was not until the emperor himself again reached the front, about 5.30 p.m., that vigour replaced indecision. There was a brief bombardment, and then Vandamme's corps was sent forward with the bayonet to drive out the foe. The shock was too great; the Prussians gave way immediately and were chased back into the woods by cavalry. Grouchy now pushed on towards Fleurus, which was still held by Blücher's troops, and there the advance came to a halt, as the light was failing and the troops exhausted.
Thus, thanks to Zieten's fine delaying action, Blücher by nightfall on June 15 had secured most of the ground requisite for his pre-arranged concentration, for one corps was in position, and two others were at hand. Bülow's corps was unavailable, for the reason already given, but of this fact Blücher was still necessarily ignorant Wellington, owing to his original dispositions and the slowness of his concentration, had only retained a grip on Quatre Bras thanks to the boldness of his subordinates on the spot. His other troops were assembling: I. Corps, Nivelles, Brainc-le-Comte and Enghien, II. Corps, Ath, Grammont and Sotteghem, heavy cavalry at Ninove; Reserve at Brussels During the night of the 15th orders were sent for the divisions to move eastwards towards Nivelles, and at dawn the Reserve marched for Mt. S. Jean. Thus Wellington did not even yet realize the full significance of the emperor's opening moves.
But if the intelligence which the duke rightly relied on had come to hand on the 15th, it cannot be doubted that he would have effected a more expeditious concentration on his inner flank. His trusted intelligence officer, Colonel Colquhoun Grant, was at this time in France, and it had been arranged that his reports should be received at the duke's outposts by General Dörnberg, for transmission to the duke. On June 15 Grant wrote to Wellington stating that the French were advancing, and that French officers spoke freely about a decisive action being fought within three days. But Dörnberg, arrogating to himself the right
