When Wellington awoke on the morning of Saturday in Genappe, there were rumours in the place that the Prussians had been defeated the day before at Ligny. The Duke went at once to Quatre Bras; sent Colonel Gordon off eastward with a detachment of the Tenth Hussars to find out what had happened, and that officer, finding the road from Ligny in the hands of the French, had the sense to scout up northwards, came upon the tail of the Prussian retreat, and returned to Wellington at Quatre Bras by half-past seven with the whole story: the Prussians had indeed been beaten; they were in full retreat; but a chance of retreat had lain open towards the north, and that was the road they had taken. Wellington knew, therefore, before eight o'clock on that Saturday morning, that his whole left or eastern flank was exposed, and it was common-sense to expect that Napoleon, with the main body of the French, having defeated the Prussians at Ligny, would now march against himself, come up upon that exposed flank (while Ney held the front), and so outnumber the Anglo-Dutch under the Duke's command. At the worst that command would be destroyed; at the best it could only hope, if it gave time for Napoleon to come up, to have to retreat westward, and to lose touch, for good, with the Prussians. In such a plight it was Wellington's business to retreat towards the north, so as to remain in touch with his Prussian allies, while yet that line of retreat was open to him, and before Napoleon should have forced a battle. [Illustration: Sketch showing the situation in which Wellington was at Quatre Bras on the morning of the 17th.] The Duke was in no hurry to undertake this movement, for as yet there was no sign of Napoleon's arrival. The men breakfasted, and it was not until ten o'clock that the retreat began. He sent word back up the road to stop the reinforcements that were still upon their way to join him at Quatre Bras, and to turn them round again up the Brussels road, the way they had come, until they should reach the ridge of the Mont St Jean, just in front of the village of Waterloo, where he had determined to stand. This done, he made his dispositions for retirement, and a little after ten o'clock the retreat upon Waterloo began. His English infantry led the retreat, the Netherland troops following, then the Brunswickers, and the last files of that whole great body of men were marching up the Brussels road northward before noon. Meanwhile, Lord Uxbridge, with his very considerable force of cavalry and the guns necessary to support it, deployed to cover the retreat, and watched the enemy.