Saunders, Tim The Talavera Campaign 1809

Lieutenant General Sir Arthur Wellesley returned to the Peninsular in 1809 convinced that the country could be held against the French. His audacious crossing of the Duoro and speedy victory at Oporto in May, followed by the deceptively easy ejection of Marshal Soults corps, confirmed this view, giving him the confidence to plan a campaign with General Cuestas Army of Extremadura to advance on French-held Madrid via the Tagus Valley.
From the outset relations between the two allied generals were poor, not to mention the divisions and enmity within the Spanish juntas and army. Matters only got worse once Wellesleys army entered Spain, thanks to a failure to provide supplies and missed opportunities. Finally, the French army, with King Joseph at its head, marched to confront the allies at Talavera.
The fighting did not start well for the British, who were taken by surprise and had to fight hard to extricate themselves from trouble, before inexperienced staff officers and commanders mis-deployed divisions and brigades, nearly resulting in disaster for the Allies when Marshal Victor launched a night attack. The Peninsular Army still had much to learn.

The following day, the French attacked again with the full force of a Napoleonic army infantry, cavalry and artillery, but the two-deep British line held and with their confidence shattered, the French withdrew. It was a hard-fought victory for the British commander, who was soon to be ennobled as the Duke of Wellington.