After the famous days of May 2nd in Madrid and the insurrection generalized throughout Spain that followed it (topic to be treated by more erudite people and that it has made and it will make traverse rivers of ink), the Spanish Army was reorganized to face to till then allied French Armies, and new armies and units were created in the free zones of the French military domain.

One of these zones was the kingdom of Galicia, where troops were constructed coming from the garrisons quartered in the region, navy warehouses (Ferrol) and even troops that up to the moment worked with the French ones in Portuguese territory and that they played the role of the former ally his new enemy.

Another area of insurrection was Asturias, where its self-proclaimed Governing Body raised a numerous quota of regiments in the diverse areas of its geography, supplied partly with material proceeding from the former enemy, England, which found an unexpected ally in the Spanish people.

In Castilian and Leonese lands units were grouped, perhaps of garrisons without French control of the region, perhaps of units that were returning from Portugal after retiring or facing up to directly the French Army.

The culminating point of these movements in the peninsular Northwest was the defeat of these armies in Medina de Rioseco, on July 14th , 1808. With it the imperial armies controlled the zone, but the remains of these armies were regrouped in the peripheral zones and of difficult control because of its geography, since it was Galicia, Asturias and the west of the current province of León.

In the rest of the Peninsula the situation was similar; even so the French Armies suffered some setbacks, like the consecutive minor defeats  in El Bruc in June 1808, the impossibility of stopping the rebellions of Zaragoza and Gerona (the first places of both), or Cádiz. Though they had the sufficient domain as in order that Jose Bonaparte, Emperor’s brother, should be come to the throne in Madrid as the Spanish King.

But that summer in Spain it must occur a fact of arms with world repercussion: for the first time a whole Imperial French Army is beaten in conventional battle and obliged to surrender as a whole. This occurs July 22nd , 1808 in the surroundings of Bailén, at the foot of Despeñaperros.

To this battle the French defeats happen at the hands of British and Portuguese Army in Vimeiro and Roliça. In view of the awkward situation, the King Jose was obliged to evacuate the court from Madrid and he retires with the remains of the French Army towards the frontier zone with France, being the court established in Vitoria.

The Governing Body established in Madrid attacks the reorganization of all the Spanish Armies and elaborates a plan to have just expelled the enemy of Spain, and even ingenuously to invade France. The forces are grouped in 4 Armies; those of the Right, Centre, Left side and Reserve.

The Left´s Army, which occupies us, agglutinates the remaining troops of that Army of Galicia beaten in Medina de Rioseco, besides regiments of new formation or reorganized in this space of time. It was put in charge of the Irish general Mr. Joaquín Blake and Joyes, and he was entrusted the mission to remove the Frenchmen from Bilbao, Vizcaya and Guipuzcoa, and across these provinces the invasion of France, while the rest of the armies were doing the same thing in their corresponding demarcations, in Navarre, Aragon, Rioja and Burgos.

From their positions they met in León, and from there, and through Palencia´s mountain, Aguilar de Campóo, Reinosa, Soncillo, Villarcayo, Espinosa and Valmaseda, in order to arrive to Bilbao, where they removed to the French garrison on October 20th , 1808.