On the 27th they early crossed the Gave de Pau; and moved by the great road which leads from Peyrehorade towards the town of Orthez; and when within about two miles of it, turning to the left, they ascended the ridge which runs parallel with the river and in front of which the French were posted in a very strong position. Whether it was that the Light Division was weak, two of its regiments being absent, or that they were not needed, the two Battalions were not actively engaged. Lord Wellington was in front of them during the afternoon, and ordered that advance of the 52nd which, as is well known, broke through Soult’s centre and decided the fate of the day.
Then the enemy fled, and then the Riflemen were ordered in pursuit, but did not come up with the retreating columns. Their march continued for about two leagues, in the course of which they passed the river Lys de Béarn and bivouacked near the village of Bonne Garde. They were entirely without covering and suffered much; for it froze hard. The Commanding Officer of the 3rd Battalion (whether Ross or Balvaird, I am not sure) did indeed contrive to get into a hut; but there being no bed unoccupied, he lay down in a kneading-trough or flour-bin, and appeared in the morning more like a miller than a Rifleman.
On the 28th the two Battalions started early, and after crossing the Lys de France, arrived at Duerse, where they halted for the night.
On March 1, they passed the Adour, and after a long march entered Mont-de-Marsan, which the enemy evacuated just before they reached it. Here they were quartered in good houses, and had comfortable beds: a change very refreshing to them after their long marches, often in very bad weather, and after their exposed bivouacks.
On the next day the 2nd Battalion marched to Bertam, and the 3rd Battalion to St. Maurice; the march was through the pine forests and by the sandy roads of the Landes; and being made in a snow storm was very painful to the soldiers.
On the next day the 3rd Battalion moved on to St. Sever, where Lord Wellington had fixed his head-quarters. Here they continued till the 8th, furnishing the guards and duties of head-quarters. On the 4th the 2nd Battalion had marched to Bascom, where they remained till the 9th, when both Battalions re-united near Aire, whither the 3rd Battalion had marched, crossing the Adour on the 8th and moving to Grenade; and next day to Barcelonne opposite Aire on the right bank of that river.