Thus the temporary separation of the four corps composing the Prussian army worked no harm. The corps-commanders acted with cheerful and zealous coöperation in the absence of orders from the commander-in-chief. In fact nothing can be finer than the spirit displayed by the Prussians after the loss of the battle of Ligny,—whether we look at their willingness to take risks and make sacrifices to ensure the success of the combined movement now in process of execution, or at the harmony which prevailed among the chief officers, which it is evident neither the loss of the battle nor the non-arrival of Bülow’s Corps had disturbed in the least. Orders were now issued for the retreat of the whole army on Wavre. It was conducted as follows:—[531] The Ist Corps marched from its position between Tilly and Mellery early in the morning of the 17th, and proceeded through Gentinnes and Mont St. Guibert towards Wavre, where it crossed the Dyle, and took up position at Bierges. The IId Corps followed by the same route somewhat later, and halted at Aisemont, a village on the south side of the Dyle, opposite Wavre. The IIId Corps rested at Gembloux till 1 or 2 o’clock P.M., and then marched by way of Corbaix to Wavre, the head of the column passing through the town in the evening, but the rear guard not arriving till the morning of the 18th. The IVth Corps marched in two columns, by way of Walhain and Tourinnes to Dion-le-Mont, a village about two miles east of Wavre, where it arrived about 10 P.M. of the 17th. One brigade of infantry belonging to the IId Corps and some cavalry were stationed for a time at Mont St. Guibert for purposes of observation,[532] and General Groeben, of Blücher’s staff, who accompanied these troops, witnessed from a high hill near Tilly[533] the march of the troops which Napoleon carried with him to Quatre Bras, and the movement of a smaller body, estimated by him at about 12,000 or 15,000 men, in the direction of Gembloux. He supposed, naturally, that this was all the force which had been detached for the pursuit of the Prussians.[534] The march of the rest of Grouchy’s command was concealed by the inequalities of the ground. The artillery trains, containing the needful ammunition for the coming battle, for the arrival of which Gneisenau had felt great anxiety, arrived safely at Wavre about 5 P.M. of the 17th. Thus the retreat of the Prussians on Wavre had been successfully and quickly accomplished, and, what is almost as important, it had escaped the observation of the French. Marshal Blücher had collected at Wavre somewhere about 90,000 men, and both the army and its leaders were animated by the best spirit, impatient to encounter the enemy again, and confident of success in another battle.