Meanwhile the French right wing, of which Grouchy had received the command, though Napoleon in person was its moving force, had been pressing the Prussians hard near Gilly.  Yet here, too, the assailants were weakened by the absence of the corps of Vandamme and Gerard.  Irritated by Ziethen’s skilful withdrawal, the Emperor at last launched his cavalry at the Prussian rear battalions, four of which were severely handled before they reached the covert of a wood.  With the loss, on the whole, of nearly 2,000 men, the Prussians fell back towards Ligny, while Grouchy’s vanguard bivouacked near the village of Fleurus.

Napoleon might well be satisfied with the work done on June 15th:  he rode back to his headquarters at Charleroi, “exhausted with fatigue,” after spending wellnigh eighteen hours in the saddle, but confident that he had sundered the allies.  This was certainly his aim now, as it had been in the campaign of 1796.  After two decisive blows at their points of connection, he purposed driving them on divergent lines of retreat, just as he had driven the Austrians and Sardinians down the roads that bifurcate near Montenotte.  True, there were in Belgium no mountain spurs to prevent their reunion; but the roads on which they were operating were far more widely divergent.[483] He also thought lightly of Wellington and Bluecher.  The former he had pronounced “incapable and unwise”; as for Bluecher, he told Campbell at Elba that he was “no general”; but that he admired the pluck with which “the old devil” came on again after a thrashing.

Unclouded confidence is seen in every phrase of the letters that he penned at Charleroi early on the 16th.  He informs Ney that he intends soon to attack the Prussians at Sombref, if he finds them there, to clear the road as far as Gembloux, and then to decide on his further actions as the case demands.  Meanwhile Ney is to sweep the road in front of Quatre Bras, placing his first division two leagues beyond that position, if it seemed desirable, with a view to marching on Brussels during the night with his whole force of about 50,000 men.  The Guard is to be kept in reserve as much as possible, so as to support either Napoleon on the Gembloux road, or Ney on the Brussels road; and “if any skirmish takes place with the English, it is preferable that the work should fall on the Line rather than on the Guard.”  As for the Prussian resistance, Napoleon rated it almost as lightly as that of the English; for he regards it as probable that he will in the evening march on Brussels with his Guard.

While he pictured his enemies hopelessly scattered or in retreat, they were beginning to muster at the very points which he believed to be within his grasp.  At 11 a.m. only Ziethen’s corps, now but 28,000 strong, was in position at Sombref, but the corps of Pirch I. and Thielmann came up shortly after midday.  Had Napoleon pushed on early on the 16th, he must easily have gained the Ligny-Sombref position.  What, then, caused the delay in the French attack?  It can be traced to the slowness of Gerard’s advance, to the Emperor’s misconception of the situation, and to his despatch to Grouchy.