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 thousand being cavalry; but the Spanish regulars under Giron, Labispal and Carlos D’España, including Longa’s division and some of Mendizabal’s 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.