On the 21st October began the memorable retreat from Burgos--a retreat which proved almost as arduous as that to Corunna, nearly four years before. The weather was generally severe, and the enemy pressed the pursuit vigorously, ever engaging the cavalry of the rearguard and sometimes making captures. The rivers were in flood and seldom passable save at the bridges, facts which gave the advantage to Wellington, whose engineers, now adept at mines and explosions, blew up each bridge as it was crossed, and thus from time to time checked the French onslaught. In this way, by the 26th October, Wellington was behind the Pisuerga river, with the mined bridge at Cabezon between him and the enemy, and thence he despatched parties to secure the bridges in his rear--viz., at Tudela and Tordesillas on the Douro, and at Valladolid and Simancas on the Pisuerga. The 7th Division was employed in holding the three last-named bridges, the 51st being responsible for that at Valladolid. The French came on swiftly, and leaving a division in front of Wellington's main body, threw out their right and swept down on the post held by the 51st. Opening from the high ground on the opposite bank with cannon and musketry, the enemy soon rendered the bridge untenable; but the company of the 51st defending it, even after the lieutenant in command had been borne to the rear with his right arm shattered, gallantly held on until the mine was ready. Then, having lost three men killed and fourteen wounded, the company withdrew rapidly as the bridge was blown up. The bridge at Simancas, being similarly menaced, was also destroyed, as was that at Tordesillas, on the 28th, by a party of the Brunswick Oels Corps detached for the purpose. But the destruction of the latter bridge was of little avail, for it was followed by an act of daring gallantry on the part of the French, perhaps without parallel in the history of war. Riding up to the broken bridge, the Frenchmen, annoyed at finding it impassable, hesitated for a moment, but then, dismounting, they set to work to form a small raft, upon which they placed their arms and clothes. Napier tells the story of what followed, and it is worth repeating. "Sixty officers and non-commissioned officers," he says, "then plunged into the water with their swords between their teeth, swimming, and pushing the raft before them. Under the protection of a cannonade they thus crossed this great river, though it was in full and strong water and the weather very cold, and having reached the other side, naked as they were, stormed the tower, whereupon the Brunswickers, amazed at the action, abandoned their ground, leaving the gallant Frenchmen masters of the passage."