With such a determination, he spared no pains in fortifying and strengthening these places; the range of positions connected with them extended from the Tagus at Alhandra, to the sea at the mouth of the Zizandra; the accessible points were occupied with forts; and every resource was employed to make a line of defence, in which so eventful a contest was to be decided, as formidable as art, combined with its natural advantages, could render it. The early decision of Lord Wellington was supported by the events which succeeded each other in the early parts of the year 1810. The great force of the enemy which menaced Portugal, and the total destruction of all the effective Spanish armies which could co-operate with the British in defence of it, confirmed Lord Wellington in the wisdom of his plan of retreat. The French had a force in Spain of not less than 300,000 men; this army was distributed over almost every part of the country; Gallicia, Valencia, and Murcia, were the only provinces that were free, the rest were in the occupation of the enemy. The amount of this force, when collected, was sufficient to overwhelm the small numbers of the allies that were in a state of military organization in the Peninsula; but from great extension, it became unequal to the task imposed upon it. It was employed in completing the subjugation of the provinces that had been conquered; and yet that object was not advancing, although the force was frittered away in seeking to accomplish it. The animosity of the people was working in silence the destruction of the French armies. Every succeeding day brought reports of skirmishes, or individual rencontres, in which the enemy were worsted, and no account represented any part of Spain as diminishing in its hostility, or as being treated with more confidence, or relied upon with greater security, by the French.
The army of Marshal Massena, while attempting the conquest of Portugal, could lend no aid towards the reduction of the people in the Peninsula: as long as it was in observation of the British troops, whether on the Spanish frontier or in the lines of Lisbon, it could as little assist the views of Buonaparte in reducing the country to obedience; the destruction of Lord Wellington’s army could alone enable Massena to fulfil the objects of his Imperial Master. The preventing that catastrophe formed the basis of Lord Wellington’s plans for the campaign. He was neither strong enough, nor had he any wish, to undertake offensive operations: the state of Spain was not such as to make them advisable; they must necessarily be commenced at considerable risk against a superior army; and if they were unsuccessful, the cause of the Peninsula was lost. By the plan which Lord Wellington had determined upon, he promised to preserve his army, to increase its discipline, to augment its numbers, to draw the French into a country where their means of subsistence would be confined, and where their force would not be sufficient to maintain even their communications with the depôts, which must necessarily be placed at a distance from them.