On the morning of the 23rd, Bouttegourd and D’Espérey opened an attack on the left flank of the Prussian Guard, while the British were receiving the first serious shock of the enemy. The French centre, however, was in a very bad way. During the afternoon the 3rd Corps gave ground, retreating in some disorder to Walcourt; the 18th was also driven back. About the same time, four surprises fell crushingly upon the French command. The first was the fall of Namur, which had been looked to as pivot of the French right. Although the VII Reserve Corps did not enter the town till 8 p.m., its resistance was virtually broken in the morning. Most of the forts had been crushed by the German 11- and 16-inch howitzers; it was with great difficulty that 12,000 men, a half of the garrison, escaped, ultimately to join the Belgian Army at Antwerp, Secondly, the Saxon Army, hitherto hidden in the Ardennes and practically unknown to the French Command, suddenly made an appearance on Lanrezac’s right flank. On the 23rd, the XII Corps captured Dinant, forced the passages of the Meuse there and at Hastière, drove in the Bouttegourd Division (51st Reserve), and reached Onhaye. The 1st Corps, thus threatened in its rear, had to break its well-designed attack on the Prussian Guard, and face about eastward. It successfully attacked the Saxons at Onhaye, and prevented them from getting more than one division across the river that night, so that the retreat of the French Army from the Sambre toward Beaumont and Philippeville, ordered by Lanrezac on his own responsibility at 9 p.m., was not impeded. Thirdly, news arrived of the failure of the French offensive in the Ardennes. The fourth surprise lay in the discovery that the British Army had before it not one or two corps, as was supposed until the afternoon of August 23, but three or four active corps and two cavalry divisions of Kluck’s force, a part of which was already engaged in an attempt to envelop the extreme left of the Allies. Only at 5 p.m.——both the intelligence and the liaison services seem to have failed——did the British commander, who had been holding pretty well since noon against attacks that did not yet reveal the enemy’s full strength, learn from Joffre that this force was twice as large as had been reported in the morning, that his west flank was in danger, and that “the two French reserve divisions and the 5th French Army on my right were retiring.” About midnight the fall of Namur and the defeat of the French 3rd and 4th Armies were also known. In face of this “most unexpected” news, a 15-miles withdrawal to the line Maubeuge–Jenlain was planned; and it began at dawn on the 24th, fighting having continued through the previous night.