At daybreak on the 16th the 51st (with Mitchell's brigade) left Grammont for Braine le Comte, where, after a weary march, it halted for the night in pouring rain. During the march the sounds of guns were distinctly heard in the distance, yet no one in the regiment knew what was taking place, or the whereabouts of the enemy. But not far away stirring events had been in progress. At 11 A.M. Wellington, riding from Brussels, had reached the position which his advanced troops were taking up at Quatre Bras, though by that time only some 7000 Dutch and Belgians, under the Prince of Orange, had arrived. Fortunately, however, Napoleon appeared to be directing all his energies against Blücher's 80,000 Prussians, in the neighbourhood of Ligny, and Wellington rode across to confer with the Prussian Field-Marshal, eventually agreeing to go to his assistance at 4 P.M., if not himself attacked. Wellington then returned to Quatre Bras, and within a couple of hours realised that the Prussians would have to look after themselves; for Napoleon, aiming at a double victory, sent Ney against Wellington early in the afternoon, and the battle which raged around Quatre Bras for the remainder of the day only ended in a victory for Wellington by the timely arrival of the reserves from Brussels. Blücher, in the meanwhile, had been severely handled by Napoleon, who, after a bloody conflict of nearly six hours, succeeded in breaking the centre of the Prussian line and driving the defeated army from the field. But of the forced retreat of his Prussian allies from Ligny Wellington heard nothing definite until next morning, when he learned that Blücher had retired upon Wavre. No sooner did Wellington become aware of the Prussian retreat than he decided to fall back from Quatre Bras to the position at Waterloo which he had had in his mind all along, and at about 10 A.M. on the 17th June he sent word to Blücher that he would fight at Waterloo if a Prussian corps would join him there. He then issued orders for the retirement from Quatre Bras, and sent instructions to Prince Frederic's Dutch-Belgians and such troops of the 4th Division as were at Braine le Comte or on the road to Nivelles to assemble at the former of these two places and await orders, while all other troops were to retire at once to Waterloo. Now it happened that Mitchell's brigade alone of the 4th Division, marching early from Braine le Comte, had reached Nivelles before the order arrived, and thus avoided sharing in the ill-luck which befell the remainder of the division--viz., being posted on the flank at Tubize, near Hal, while the great victory of the 18th June was being won.[81] Mitchell, therefore, paraded his brigade with the 2nd Division, already at Nivelles; and at noon the 51st was marching north by the Brussels road.