The regiment was subsequently employed in attempting to intercept the French division under General Clausel, and when this force had escaped to France, the regiment proceeded to Pampeluna, to take part in the blockade of that fortress, from which duty it was relieved by a Spanish corps, on the 14th of July, and advanced into the Pyrenean Mountains to San Estevan, situated in a beautiful valley, where it halted. Thus, after marching nearly six hundred miles in seven weeks, passing six great rivers, gaining one decisive battle, and investing the two fortresses of Pampeluna and San Sebastian, the allied army stood triumphant on the lofty Pyrenees, and the officers and soldiers panted for opportunities to acquire additional honors. The French army having been reinforced, and reorganized, advanced under Marshal Soult, and attacked the British posts in the mountains, when the allied army fell back to a position in front of Pampeluna. The sixth division, to which the SIXTY-FIRST continued to belong, quitted San Estevan to support the troops first attacked; but when advancing, Lord Wellington rode up to the division, and ordered it to halt for the night. It afterwards retired through the mountain passes, and bivouacked, during the night of the 27th of July, in a pine-wood. At daybreak on the following morning it resumed its march, and joining the army in position in the mountains, formed for battle across the valley in the rear of the left of the fourth division, its right on the village of Oricain, and its left on some heights. Soon after the regiment had taken its post, columns of attack were seen in motion to commence the battle of the _Pyrenees_, where the SIXTY-FIRST had another opportunity of distinguishing themselves. A body of French troops moved along the valley of Lanz towards the mountain at its extremity, and the SIXTY-FIRST, with two other British corps, were ordered to move at a running pace and occupy the mountain. The SIXTY-FIRST hastened up the hill on one side, as the French skirmishers ascended on the other; but the British gained the summit first, and opened their fire with terrible effect. The French were encompassed in the valley; two brigades smote them from the left, the Portuguese smote them from the right, and the sixth division forced them back with a terrible carnage. The enemy retreated behind the village of Sauroren. The SIXTY-FIRST, and two other regiments, advanced to a post near the village, and the fire of small-arms was kept up until dark.