On the left of Hill the seventh and light divisions occupied a chain of mountains running by Echallar to Vera, and behind them at the town of San Estevan was posted the sixth division.
Longa’s Spaniards continued the line of defence from Vera to general Giron’s position, which extending along the mountains bordering the Bidassoa to the sea, crossed the great road of Irun. Behind Giron was the besieging army under sir Thomas Graham.
Thirty-six pieces of field artillery, and some regiments of British and Portuguese cavalry, were with the right wing and centre, but the bulk of the horsemen and the heavy guns were behind the mountains, chiefly about Tafalla. The great hospitals were in Vittoria, the commissariat depôts were principally on the coast, and to supply the troops in the mountains was exceedingly difficult and onerous.
Henry O’Donnel, Conde de la Bispal, blockaded Pampeluna with the Andalusian army of reserve, and Carlos D’España’s division was on the march to join him. Mina, Julian Sanchez, Duran, Empecinado, Goyan and some smaller bands, were on the side of Zaragoza and Daroca, cutting the communication between Soult and Suchet, and the latter, thinking Aragon lost, was, as we have seen, falling back upon Catalonia.
The whole force under lord Wellington’s immediate command, that is to say in Navarre and Guipuscoa, was certainly above one hundred thousand men, of which the Anglo-Portuguese furnished fifty-seven thousand present under arms, seven[Appendix, 7.] thousand being cavalry; but the Spanish regulars under Giron, Labispal and Carlos D’España, including Longa’s division and some of Mendizabal’sNotes by the Duke of Wellington, MSS. army, scarcely amounted to twenty-five thousand. According to the respective muster-rolls, the troops in line actually under arms and facing each other, were, of the allies, about eighty-two thousand, of the French about seventy-eight thousand; but as the rolls of the latter include every man and officer of all arms belonging to the organization, and the British and Portuguese rolls so quoted, would furnish between ten and twelve thousand additional combatants, the French force must be reduced, or the allies augmented in that proportion. This surplus was however now compensated by the foreign battalions temporarily attached to Soult’s army, and by the numerous national guards, all mountaineers, fierce warlike and very useful as guides. In other respects lord Wellington stood at a disadvantage.
The theatre of operations was a trapezoid, with sides from forty to sixty miles in length, and having Bayonne, St. Jean Pied de Port, St. Sebastian and Pampeluna, all fortresses, in possession of the French at the angles. The interior, broken and tormented by dreadful mountains, narrow craggy passes, deep water-courses, precipices and forests, would at first sight appear a wilderness which no military combinations could embrace, and susceptible only of irregular and partizan operations. But the great spinal ridge of the Pyrenees furnishes a clue to the labyrinth of hills and valleys. Running diagonally across the quadrilateral, it separated Bayonne St. Jean Pied de Port and San Sebastian from Pampeluna, and thus the portion of the allied army which more especially belonged to the blockade of Pampeluna, was in a manner cut off from that which belonged to the siege of San Sebastian. They were distinct armies, each having its particular object, and the only direct communication between them was the great road running behind the mountains from Toloza, by Irurzun, to Pampeluna. The centre of the allies was indeed an army of succour and connection, but of necessity very much scattered, and with lateral communications so few, difficult and indirect as to prevent any unity of movement; nor could general Hill’s corps move at all until an attack was decidedly pronounced against one of the extremities, lest the most direct gun-road to Pampeluna which it covered should be unwarily opened to the enemy. In short the French general, taking the offensive, could by beaten roads concentrate against any part of the English general’s line, which, necessarily a passively defensive one, followed an irregular trace of more than fifty miles of mountains.
Wellington having his battering train and stores about San Sebastian, which was also nearer and more accessible to the enemy than Pampeluna, made his army lean towards that side. His left wing, including the army of siege, was twenty-one thousand strong with singularly strong positions of defence, and the centre, about twenty-four thousand strong, could in two marches unite with the left wing to cover the siege or fall upon the flanks of an enemy advancing by the high road of Irun; but three days or more were required by those troops to concentrate for the security of the blockade on the right. Soult however judged that no decisive result would attend a direct movement upon San Sebastian; because Guipuscoa was exhausted of provisions, and the centre of the allies could fall on his flank before he reached Ernani, which, his attack in front failing, would place him in a dangerous position. Moreover by means of his sea communication he knew that San Sebastian was not in extremity; but he had no communication with Pampeluna and feared its fall. Wherefore he resolved to operate by his left.
Profiting by the roads leading to St. Jean Pied de Port, and covering his movement by the Nivelle and Nive rivers and by the positions of his centre, he hoped to gather on Wellington’s right quicker than that general could gather to oppose him, and thus compensating by numbers the disadvantage of assailing mountain positions force a way to Pampeluna. That fortress once succoured, he designed to seize the road of Irurzun, and keeping in mass either fall upon the separated divisions of the centre in detail as they descended from the hills, or operate on the rear of the force besieging San Sebastian, while a corps of observation, which he proposed to leave on the Lower Bidassoa, menaced it in front and followed it in retreat. The siege of San Sebastian, the blockade of Pampeluna and probably that of Santona, would be thus raised, and the French army united in an abundant country, and its communication with Suchet secured, would be free either to co-operate with that marshal or to press its own attack.
In this view, and to mislead lord Wellington by vexing his right simultaneously with the construction of the bridges against his left, Soult wrote to general Paris, desiring him to march when time suited from Jaca by the higher valleys towards Aviz or Sanguessa, to drive the partizans from that side and join the left of the army when it should have reached Pampeluna. Meanwhile Clauzel was directed to repair the roads in his own front, to push the heads of his columns towards the passes of Roncesvalles, and by sending a strong detachment into the Val de Baygorry, towards the lateral pass of Yspegui, to menace Hill’s flank which was at that pass, and the front of Campbell’s brigade in the Alduides.
On the 20th Reille’s troops on the heights above Vera and Sarre, being cautiously relieved by Villatte, marched through Cambo towards St. Jean Pied de Port. They were to reach the latter early on the 22d, and on that day also the two divisions of cavalry and the park of artillery were to be concentrated at the same place. D’Erlon with the centre meanwhile still held his positions at Espelette, Ainhoüe or Ainhoa, and Urdax, thus covering and masking the great movements taking place behind.