Ney now realized that he could only capture Quatre Bras with D'Erlon's help.
Corps was carrying out, strove to induce Ney to reconsider D'Erlon's recall; but the marshal refused and ended the discussion by plunging into the fight.
At 9 P.M., when the battle was lost and won, D'Erlon's corps arrived.
When the battle was ripe, he would crush the Prussian centre and right between the Guard and D'Erlon's corps.
Immediately afterwards, hearing that Ney had 20,000 men in front of him, he sent the "pencil-note" by General La Bedoyere which directed Ney to detach D'Erlon's corps to Ligny.
But hardly had the Young and Middle Guard marched off to reinforce Vandamme and Gerard, when Vandamme sent word that a hostile column, over 30,000 strong, was threatening the French left (in reality this was D'Erlon's corps).
It was about 6.30 before Napoleon learned that the unknown force was actually D'Erlon's, and somewhat later he heard that it had counter-marched and withdrawn westwards.
Despite D'Erlon's misadventure the emperor had the game still in his hands, for Ney's failure had actually placed the AngloDutch army in a precarious position.
The emperor having beaten Blucher, the latter must fall back to rally and re-form, and call in Billow, who had only reached the neighbourhood of Gembloux on June 16; whilst on the other flank Ney, reinforced by D'Erlon's fresh corps, lay in front of Wellington, and the marshal could fasten upon the Anglo-Dutch army and hold it fast during the early morning of June 17, sufficiently long to allow the emperor to close round his foe's open left flank and deal him a deathblow.
Scale, i :36,000 English Miles Ney was therefore ordered to attack Wellington's centre with D'Erlon's corps.
As D'Erlon's troops advanced the Dutch-Belgian brigade in front of the ridge, which had been subjected to an overwhelming fire from the 80 French guns at close range, turned about and retired in disorder through the main position.
Corps; for the left division failed to storm La Haye Sainte, which was most gallantly defended, and Picton's division met the remainder of D'Erlon's corps face to face, engaging them in a murderous infantry duel in which Picton fell.
Napoleon now ordered Ney to carry La Haye Sainte at whatever cost, and this the marshal accomplished with the wrecks of D'Erlon's corps soon after 6 P.M.