He was opportunely reinforced, and gave battle on the rugged heights in front of Pamplona to a force numerically superior, but for the most part charging uphill. Never, even at Bussaco, did the French show greater ardour and _élan_ in attack, and it was only after a series of bloody hand-to-hand combats on the summits and sides of the mountains that they were compelled to recoil and rolled backward down the ridge. Baffled in his attempt to relieve Pamplona, Soult turned westwards towards St. Sebastian, but was anticipated by Wellington, and faced by three divisions of Hill on his right. A second engagement followed, in which the Portuguese earned the chief honours, and 3,000 prisoners were taken. At last Soult gave orders for a retreat, and in the course of it was all but entrapped in a narrow valley where he could not have escaped the necessity of surrender. It is said that he was warned just in time by the sudden intrusion of three British marauders in uniform; at all events, he instantly changed his line of march, and ultimately led his broken army back to France, but in the utmost confusion, and not without fresh disasters. One of these befell Reille's division in the gorge of Yanzi, and another the French rear-guard under Clausel, which defended itself valiantly, but was driven headlong down the northern side of the Pyrenees from which this series of battles derives its name. The siege of St. Sebastian was immediately renewed with a far more powerful battering train, but its defences had also been strengthened by the indefatigable governor. The final assault took place on August 31, and rivalled the storming of Badajoz in the murderous ferocity of the _melée_ at the breaches, as well as in the horrors practised on the inhabitants by the victorious assailants, which Wellington and Graham vainly endeavoured to check. So desperate was the defence, and so insuperable appeared the obstacles to an entrance by the breaches, that Graham adopted the heroic expedient of causing his artillery to fire a few feet only over the heads of the forlorn hope, until a clear opening had been made, and deadly piles of combustibles had been exploded behind the main breach, blowing into the air 300 of the garrison. A hideous conflagration destroyed the greater part of the town. A few days later the castle, to which the governor had retired, yielded to an irresistible cannonade, and he surrendered at discretion with about 1,200 men. Several hundred wounded, including a large number of British prisoners, were found there in the hospitals.