In fact, the only part of Spain that now really interested Napoleon was the north and north-east.  So long as he firmly held the provinces north of the Ebro, he seems to have cared little whether Joseph reigned, or did not reign, at Madrid.  All that concerned him was to hold the British at bay from the line of the Douro, while French authority was established in the north and north-east.  This he was determined to keep; and probably he had already formed the design, later on to be mooted to Ferdinand VII. at Valencay, of restoring him to the throne of Spain and of indemnifying him with Portugal for the loss of the north-eastern provinces.  This scheme may even have formed part of a plan of general pacification; for at Dresden, on May 17th, he proposed to Austria the admission of representatives of the Spanish insurgents to the European Congress.  But it is time to turn from the haze of conjecture to the sharp outlines of Wellington’s campaign.[315]

While the French cause in Spain was crumbling to pieces, that of the patriots was being firmly welded together by the organizing genius of Wellington.  By patient efforts, he soon had the Spanish and Portuguese contingents in an efficient condition:  and, as large reinforcements had come from England, he was able early in May to muster 70,000 British and Portuguese troops and 30,000 Spaniards for a move eastwards.  Murray’s force tied Suchet fast to the province of Valencia; Clausel was fully employed in Navarre, and thus Joseph’s army on the Douro was left far too weak to stem Wellington’s tide of war.  Only some 45,000 French were ready in the districts between Salamanca and Valladolid.  Others remained in the basin of the Tagus in case the allies should burst in by that route.

Wellington kept up their illusions by feints at several points, while he prepared to thrust a mighty force over the fords of the Tormes and Esla.  He completely succeeded.  While Joseph and Jourdan were haltingly mustering their forces in Leon, the allies began that series of rapid flanking movements on the north which decided the campaign.  Swinging forward his powerful left wing he manoeuvred the French out of one strong position after another.  The Tormes, the Esla, the Douro, the Carrion, the Pisuerga, none of these streams stopped his advance.  Joseph nowhere showed fight; he abandoned even the castle of Burgos, and, fearing to be cut off from France, retired behind the upper Ebro.

The official excuse given for this rapid retreat was the lack of provisions:  but the diaries of two British officers, Tomkinson and Simmons, show that they found the country between the Esla and the Ebro for the most part well stocked and fertile.  Simmons, who was with the famous Light Division, notes that the Rifles did not fire a shot after breaking up their winter quarters, until they skirmished with the French in the hills near the source of the Ebro.  The French retreat was really necessary in order to bring the King’s forces into touch with the corps of Generals Clausel and Foy, in Navarre and Biscay respectively.  Joseph had already sent urgent orders to call in these corps; for, as he explained to Clarke, the supreme need now was to beat Wellington; that done, the partisan warfare would collapse.