Prussian troops are on their way. For the first time, the emperor realizes that the defeated Prussians must have eluded pursuit to join the British early, while a third of his own troops are manoeuvring uselessly in open country. He immediately writes Grouchy a letter telling him at all costs to keep in contact with the Prussians and prevent them from joining the battle.

At the same time Marshal Ney receives the order to attack. Wellington must be repelled before the Prussians arrive. No risk seems too great to take now that the chances are so suddenly reduced. All afternoon ferocious attacks on the plateau go on, and the infantry are always thrown back again. Again they storm the ruined villages, again and again they are smashed to the ground, again and again the wave of infantrymen rises, banners fluttering, to advance on the squares of their adversaries. Wellington still stands firm, and still there is no news of Grouchy. “Where is Grouchy? Where can he be?” murmurs the emperor nervously as he sees the Prussian advance guard gradually gaining ground. The commanding officers under him are also feeling impatient. And, determined to bring the battle to a violent end, Marshal Ney—as recklessly bold as Grouchy is over-thoughtful (three horses have already been shot under him)—stakes everything on throwing the entire French cavalry into action in a single attack. Ten thousand cuirassiers and dragoons attempt that terrible ride of death, smashing through the squares, cutting down the gunners, scattering the rows of men in front. They in turn are repelled again, true, but the force of the British army is failing, the fist holding those hills tightly in its grasp is beginning to slacken. And now, as the decimated French cavalry gives ground, Napoleon’s last reserve troops, the Old Guard, move forward heavily, slow of step, to storm the hill whose possession will guarantee the fate of Europe.

The Moment of Decision

Four hundred cannon have been thundering without a break since morning on both sides. At the front, the cavalcades of horsemen clash with the firing squares, drumsticks come down hard on the drumheads, the whole plain is shaking with the noise. But above the battle, on the two hills, the field marshals are listening to a softer sound above the human storm.

Above the stormy crowds, two watches are ticking quietly like birds’ hearts in their hands. Both Napoleon and Wellington keep reaching for their chronometers and counting the hours and minutes that must bring those last, crucial reinforcements to their aid. Wellington knows that Blücher is near, Napoleon is hoping for Grouchy. Neither of them has any other reserves, and whoever brings his troops first has decided the course of the battle. Both commanders are looking through telescopes at the outskirts of the woods, where the Prussian vanguard begins to appear in the form of a light cloud. But are those only a few men skirmishing, or the army itself in flight from Grouchy? The British are putting up their final resistance, but the French troops too are weary. Gasping like two wrestlers, the troops face each other with arms already tired, getting their breath back before they attack one another for the last time. The irrevocable moment of decision has come.

Now, at last, the thunder of cannon is heard on the Prussian flank, with skirmishing and rifle fire from the fusiliers. “Enfin Grouchy!” Grouchy at last! Napoleon breathes a sigh of relief. Trusting that his flank is now secure, Napoleon gathers together the last of his men and throws them once more against Wellington’s centre, to break the defensive wall outside Brussels and blow open the gateway to Europe.

But the gunfire was only part of a mistaken skirmishing that the approaching Prussians, confused by the uniform of the men they take for enemies, have begun against the Hanoverians. Realizing their mistake, they soon stop firing, and now the massed crowd of them—broad, powerful, unimpeded—pours out of the wood. It is not Grouchy advancing with his troops, but Blücher, and with him Napoleon’s undoing. The news spreads fast among the imperial troops, who begin to fall back, still in reasonably good order. Wellington, however, seizes this critical moment. Riding to the edge of the victoriously defended hill, he raises his hat and waves it above his head at the retreating enemy.