Battle of Salamanca and the Allied entry into Madrid

Background. The Peninsular War (1808–1814) pitted Spain, Portugal and the United Kingdom against the occupying forces of Napoleon's First French Empire. In 1812, while Napoleon led a massive army into Russia, Wellington renewed the allied advance into Spain, capturing Ciudad Rodrigo by assault on 19 January and opening the northern invasion corridor from Portugal.

The Anglo-Portuguese Army. The force Wellington led into Spain was the Anglo-Portuguese Army, not a purely British one. It had undergone training and reorganization between 1809 and 1812 and was noted for good discipline and morale. In April 1812, after the successful Siege of Badajoz, Wellington marched the greater part of this army north to expel Marmont's French army, which had temporarily invaded Portugal.

Aftermath. The allied victory at Salamanca on 22 July 1812 forced King Joseph Bonaparte to abandon Madrid on 11 August, and the combined English and Portuguese army under Wellington entered the capital the next day. The campaign's success came while Napoleon was engaged in his disastrous Russian invasion. Later that autumn, a French counteroffensive compelled Wellington to lift the siege of Burgos and retreat to Portugal, though that episode lies outside this event's scope.