What, meanwhile, was the position of the allies?  An Austro-Sardinian force threatened the south-east of France.  Mighty armies of 170,000 Russians and 250,000 Austrians were rolling slowly on towards Lorraine and Alsace respectively; 120,000 Prussians, under Bluecher, were cantoned between Liege and Charleroi; while Wellington’s composite array of British, German, and Dutch-Belgian troops, about 100,000 strong, lay between Brussels and Mons.[473] The original plan of these two famous leaders was to push on rapidly into France; but the cautious influences of the Military Council sitting at Vienna prevailed, and it was finally decided not to open the campaign until the Austrians and Russians should approach the frontiers of France.  Even as late as June 15th we find Wellington writing to the Czar in terms that assume a co-operation of all the allies in simultaneous moves towards Paris—­movements which Schwarzenberg had led him to expect would begin about the 20th of June.[474]

From this prolonged and methodical warfare Europe was saved by Napoleon’s vigorous offensive.  His political instincts impelled him to strike at Brussels, where he hoped that the populace would declare for union with France and severance from the detested Dutch.  In this war he must not only conquer armies, he must win over public opinion; and how could he gain it so well as in the guise of a popular liberator?

But there were other advantages to be gained in Belgium.  By flinging himself on Wellington and the Prussians, and driving them asunder, he would compel Louis XVIII. to another undignified flight; and he would disorganize the best prepared armies of his foes, and gain the material resources of the Low Countries.  He seems even to have cherished the hope that a victory over Wellington would dispirit the British Government, unseat the Ministry, and install in power the peace-loving Whigs.

And this victory was almost within his grasp.  While his host drew near to the Prussian outposts south of Charleroi and Thuin, the allies were still spread out in cantonments that extended over one hundred miles, namely, from Liege on Bluecher’s left to Audenarde on Wellington’s right.  This wide dispersion of troops, when an enterprising foe was known to be almost within striking distance, has been generally condemned.  Thus General Kennedy, in his admirable description of Waterloo, admits that there was an “absurd extension” of the cantonments.  Wellington, however, was bound to wait and to watch the three good high-roads, by any one of which Napoleon might advance, namely, those of Tournay, Mons, and Charleroi.  The Duke had other causes for extending his lines far to the west:  he desired to cover the roads from Ostend, whence he was expecting reinforcements, and to stretch a protecting wing over the King of France at Ghent.