Ever since two o’clock the Prussians had been operating on the French right wing. Bülow’s corps was having a bloody struggle with Lobau and the Young Guard. Time and again the Prussians were thrown back; time and again they returned to the attack. At the instant when Ney was demanding more troops, Lobau’s corps was in retreat and the Young Guard was driven out of Plancenoit. Napoleon’s own position on La Belle Alliance was threatened. To prevent the Prussians from coming upon his rear, the Emperor sent in eleven battalions of the Old Guard which, with fixed bayonets and without firing a shot, drove the Prussians out of Plancenoit and chased them six hundred yards. It was now after seven o’clock. There were still two hours of daylight. In the distance were heard the guns of Grouchy; the sound seemed to draw nearer. The Emperor, counting too much on Grouchy always, believed that at last his tardy lieutenant was engaged with the bulk of the Prussian army, and that he himself would have to deal with the corps of Bülow only. The Emperor swept the field of battle with his glass. On the right, Durutte’s division held Papelotte and La Haye and was advancing up the slope toward the English line. On the left, Jerome had stormed the burning château of Hougoumont, and the Lancers had crossed the Nivelles road. In the center, and above La Haye-Sainte, the French were driving the enemy along the Ohain road. The valley was crowded with the wrecks of broken French regiments. Placing himself at the head of nine battalions of the Old Guard, Napoleon led it down into the valley, spoke to his men briefly, and launched them against the enemy. It was too late. A deserter had given Wellington full notice of the preparations for the attack and he had thrown reinforcements into the weak portions of his line. The arrival of Zeiten’s Prussians relieved the flanking squadrons of Vivian and Vandeleur, and Wellington now had 2,600 fresh horsemen to throw into the fight. At full gallop, the Prussian Commissioner to the Allies, Muffling, rode to Zeiten, exclaiming, “The battle is lost if you do not go to the Duke’s rescue.” On came the Prussians, striking the French flank from Smohain, and in spite of all the personal exertions of the Emperor, a panic spread throughout that part of his army. Couriers had been sent all along the line to tell the French that Grouchy was approaching. Yet the battle on the right where Lobau and the Young Guard were struggling to keep Bülow back must have been known to thousands of the troops. Then, when they actually saw the Prussians taking them in flank, all their fears of treachery were intensified and they were filled with terror.