General Freyre’s Spaniards, about nine thousand strong, with six guns, were disposed on Alten’s left,Plan 6. at the fort of Calvary and towards Jollimont, ready to fall upon any troops which might be detached from the camp of Serres by the bridge of Ascain, to support Clauzel.
General Hope having the first and fifth divisions, Wilson’s, Bradford’s, and lord Aylmer’s brigades of infantry, Vandeleur’s brigade of light dragoons, and the heavy German cavalry, in all about nineteen thousand men and officers with fifty-four guns, was opposed to Soult’s right wing; and the naval squadron hovering on Hope’s left flank was to aid the land operations.
On the French side each lieutenant-general had a special position to defend. D’Erlon’s first line, its left resting on the fortified rocks of Mondarin which could not be turned, run from thence along the Choupera and Atchuleguy mountains by the forge of Urdax to the Nivelle. This range was strongly entrenched and occupied by one of Abbé’s and one of D’Armagnac’s brigades, Espelette being behind the former and Ainhoa behind the latter. The second line or main position was several miles distant on a broad ridge, behind Ainhoa, and it was occupied by the remaining brigades of the two divisions. The left did not extend beyond the centre of the first line, but the right reaching to the bridge of Amotz stretched with a wider flank, because the Nivelle flowing in a slanting direction towards the French gave greater space as their positions receded. Three great redoubts were constructed in a line on this ridge, and a fourth had been commenced close to the bridge.
On the right of D’Erlon’s second line, that is to say beyond the bridge of Amotz, Clauzel’s position extended to Ascain, also along a strong range of heights fortified with many redoubts trenches and abbatis, and as the Nivelle after passing Amotz swept in a curve completely round the range to Ascain, both flanks rested alike upon that river, having communication by the bridges of Amotz and Ascain on the right and left, and a retreat by the bridges of San Pé and Harastagui which were in rear of the centre. Two of Clauzel’s divisions reinforced by one of D’Erlon’s under general Maransin were here posted. In front of the left were the redoubts of St. Barbe and Grenada covering the village and ridge of Sarre. In front of the right was the smaller Rhune which was fortified and occupied by a brigade of Maransin’s division. A new redoubt with abbatis was also commenced to cover the approaches to the bridge of Amotz.
On the right of this line beyond the bridge of Ascain, Daricau’s division belonging to Clauzel’s corps, and the Italian brigade of San Pol drawn from Villatte’s reserve, were posted to hold the entrenched camp of Serres and to connect Clauzel’s position with Villatte’s, which was as I have before said on a ridge crossing the gorges of Olette and Jollimont. The French right wing under Reille, strongly fortified on the lower ground and partially covered by inundations, was nearly impregnable.
Soult’s weakest point of general defence was certainly the opening between the Rhune mountains and the Nivelle. Gradually narrowing as it approached the bridge of Amotz this space was the most open, the least fortified, and the Nivelle being fordable above that bridge could not hamper the allies’ movements. Wherefore a powerful force acting in this direction could pass by D’Erlon’s first line and breaking in upon the main position, between the right of that general’s second line and Clauzel’s left, turn both by the same attack.
Lord Wellington thus designed his battle. General Hill, leaving Minas four battalions on the Gorospil mountain facing the rocks of Mondarin, moved in the night by the different passes of the Puerto de Maya, Morillo’s Spaniards being to menace the French on the Choupera and Atchuleguy mountains, the second division to attack Ainhoa and Urdax. The sixth division and Hamilton’s Portuguese were to assault the works covering the bridge of Amotz, either on the right or left bank of the Nivelle according to circumstances. Thus the action of twenty-six thousand men was combined against D’Erlon’s position, and on their left Beresford’s corps was assembled. The third division under general Colville, descending from Zagaramurdi, was to move against the unfinished redoubts and entrenchments covering the approaches to the bridge of Amotz on the left bank of the Nivelle, thus turning D’Erlon’s right at the moment when it was attacked in front by Hill’s corps. On the left of the third division, the seventh, descending from the mouth of the Echallar pass, was to storm the Grenada redoubt, and then passing the village of Sarre assail Clauzel’s main position abreast with the attack of the third division. On the left of the seventh, the fourth division, assembling on the lower slopes of the greater Rhune, was to descend upon the redoubt of San Barbe, and then moving through Sarre also to assail Clauzel’s main position abreast with the seventh division. On the left of the fourth division, Giron’s Spaniards, gathered higher up on the flank of the great Rhune, were to move abreast with the others leaving Sarre on their right. They were to drive the enemy from the lower slopes of the smaller Rhune and then in concert with the rest attack Clauzel’s main position. In this way Hill’s and Beresford’s corps, forming a mass of more than forty thousand infantry were to be thrust, on both sides of the bridge of Amotz, between Clauzel and D’Erlon to break their line of battle.
Charles Alten with the light division and Longa’s Spaniards, furnishing together about eight thousand men, was likewise to attack Clauzel’s line on the left of Giron, while Freyre’s Gallicians approached the bridge of Ascain to prevent reinforcements coming from the camp of Serres. But ere Alten could assail Clauzel’s right the smaller Rhune which covered it was to be stormed. This mountain outwork was a hog’s-back ridge rising abruptly out of table-land and parallel with the greater Rhune. It was inaccessible along its front, which was precipitous and from fifty to two hundred feet high; but on the enemy’s left these rocks gradually decreased, descending by a long slope to the valley of Sarre, and about two-thirds of the way down the thirty-fourth French regiment was placed, with an advanced post on some isolated crags situated in the hollow between the two Rhunes. On the enemy’s right the hog’s-back sunk by degrees into the plain or platform. It was however covered at that point by a marsh scarcely passable, and the attacking troops were therefore first to move up against the perpendicular rocks in front, and then to file to their left under fire, between the marsh and the lower crags, until they gained an accessible point from whence they could fight their way along the narrow ridge of the hog’s-back But the bristles of the latter were huge perpendicular crags connected with walls of loose stones so as to form several small forts or castles communicating with each other by narrow foot-ways, and rising one above another until the culminant point was attained. The table-land beyond this ridge was extensive and terminated in a very deep ravine on every side, save a narrow space on the right of the marsh, where the enemy had drawn a traverse of loose stones, running perpendicularly from behind the hog’s-back and ending in a star fort which overhung the edge of the ravine.
This rampart and fort, and the hog’s-back itself, were defended by Barbot’s brigade of Maransin’s division, and the line of retreat was towards a low narrow neck of land, which bridging the deep ravine linked the Rhune to Clauzel’s main position: a reserve was placed here, partly to sustain the thirty-fourth French regiment posted on the slope of the mountain towards Sarre, partly to protect the neck of land on the side of that village. As this neck was the only approach to the French position in that part, to storm the smaller Rhune was a necessary preliminary to the general battle, wherefore Alten, filing his troops after dark on the 9th from the Hermitage, the Commissary mountain, and the Puerto de Vera, collected them at midnight on that slope of the greater Rhune which descended towards Ascain. The main body of the light division, turning the marsh by the left, was to assail the stone traverse and lap over the star fort by the ravine beyond; Longa, stretching still farther on the left, was to turn the smaller Rhune altogether; and the forty-third regiment supported by the seventeenth Portuguese was to assail the hog’s-back. One battalion of riflemen and the mountain-guns were however left on the summit of the greater Rhune, with orders to assail the craggy post between the Rhunes and connect Alten’s attack with that of Giron’s Spaniards. All these troops gained their respective stations so secretly that the enemy had no suspicion of their presence, although for several hours the columns were lying within half musket-shot of the works. Towards morning indeed five or six guns, fired in a hurried manner from the low ground near the sea, broke the stillness, but the French on the Rhune remained quiet, and the British troops awaited the rising of the sun when three guns fired from the Atchubia mountain were to give the signal of attack.