To students of military history it may seem a very doubtful question whether, under such circumstances, it was prudent to advance farther into Spain from his strongholds on the Portuguese frontier. But Wellington, who had been created a marquis on August 18, judged it necessary to crush if possible the remainder of Marmont's army which had retired northward under Clausel. He therefore left Hill with a detachment to cover Madrid, and marching through Valladolid occupied the town of Burgos. The castle of that place remained in the hands of a French garrison 2,000 strong and had been carefully fortified. Here again we may be permitted to doubt whether, after the experience gained at Ciudad Rodrigo and Badajoz, Wellington did wisely in resolving to invest and storm a fortress so formidable, without an adequate siege-train, and with the knowledge that Clausel might rally his forces in time to relieve it. Wellington himself afterwards admitted to Liverpool that he had erred in not taking with him the best of his own troops, and that he did not possess the means of transporting ordnance and military stores from Madrid and Santander, where there was abundance of them. The siege lasted a month, from September 19 to October 18; the garrison offered a most obstinate resistance, inflicting great loss on the besiegers by sorties, and in the end the attack failed. Souham, with Clausel, was closing in upon Wellington from the north, Soult from the south-east; Hill's position at Madrid was untenable, and another retreat became inevitable. It was the last and most trying in Wellington's military career. The army which had behaved nobly at Salamanca broke down under the strain of suffering and depression, like that of Sir John Moore before Coruña. The enemy was driven back in various rear-guard actions, but on the march the sense of discipline vanished and shameful disorders occurred. A scathing reprimand from Wellington, which might have been written by a French critic and which ought never to have been made public, threw all the blame of this disorganisation on the regimental officers, and denied that any scarcity of provisions could be pleaded in excuse of it. [Pageheading: _MILITARY REFORMS._]