In the course of the evening, the Duke received from Prince Blücher a reply to the request he had made for his support in the position he was now occupying. It was highly characteristic of the old man, who had written it, in the following terms, without previously conferring with, or addressing himself to, any one:—"I shall not come with two Corps only, but with my whole Army; upon this understanding, however, that should the French not attack us on the 18th, we shall attack them on the 19th."
The Duke, who, as has already been explained, had, from the commencement of the Campaign, considered it very possible that Napoleon would advance by the Mons road, still entertained apprehensions of an attempt on the part of his opponent to turn him by Hal, and seize Brussels by a coup de main. For this, however, he was fully prepared, having made his dispositions for the security of that Flank, in the manner pointed out in the following instructions, which he issued to Major General the Hon. Sir Charles Colville:—
"17th June 1815.
"The Army retired this day from its position at Quatre Bras to its present position in front of Waterloo.
"The Brigades of the Fourth Division, at Braine le Comte, are to retire at daylight tomorrow morning upon Hal.
"Major General Colville must be guided by the intelligence he receives of the Enemy's movements in his march to Hal, whether he moves by the direct route or by Enghien.
"Prince Frederick of Orange is to occupy with his Corps the position between Hal and Enghien, and is to defend it as long as possible.
"The Army will probably continue in its position in front of Waterloo tomorrow.
"Lieutenant Colonel Torrens will inform Lieutenant General Sir Charles Colville of the position and situation of the Armies."
The respective lines of Picquets and Vedettes had scarcely been taken up along the low ground that skirted the front of the Anglo-Allied position, and the last gun had just boomed from the Heights, when "heaven's artillery," accompanied by vivid flashes of lightning, again peeled forth in solemn and awful grandeur; while the rain, pouring down in torrents, imparted the utmost gloom and discomfort to the bivouacs, which the opposing Armies had established for the night, upon the ground destined to become celebrated in history, even to the remotest ages.
IT was not until the night of the 16th, after Zieten's and Pirch's Corps d'Armée had retired to Tilly and Gentinnes, that it was decided the Prussian Army should retreat upon Wavre. This decision was communicated in the Orders then transmitted from the Prussian Head Quarters to the First and Second Corps d'Armée (Zieten's and Pirch's) directing them to bivouac at Bierge and St Anne, in the vicinity of Wavre; as also in the Orders forwarded, on the next morning, to the bivouacs of the Third and Fourth Corps (Thielemann's and Bülow's), at Gembloux and Basse Bodecée, directing them to fall back, and bivouac at La Bavette and Dion le Mont near Wavre.
Zieten's and Pirch's Corps retired by Mont St Guibert, in rear of which Defile the latter Corps remained a considerable time as Rear Guard, while the former marched on to Wavre, where it arrived about midday, crossed the Dyle, and took up its position at Bierge. Pirch followed the same route, but took post on the right bank of the Dyle, between St Anne and Aisemont.