By the end of 1812, the large army that had invaded the Russian Empire, the Grande Armée, had ceased to exist. Unable to resist the oncoming Russians, the French had to evacuate East Prussia and the Grand Duchy of Warsaw. With both the Austrian Empire and the Kingdom of Prussia joining his opponents, Napoleon withdrew more troops from Spain, including some foreign units and three battalions of sailors sent to assist with the siege of Cádiz. In total, 20,000 men were withdrawn; the numbers were not overwhelming, but the occupying forces were left in a difficult position. In much of the area under French control—the Basque provinces, Navarre, Aragon, Old Castile, La Mancha, the Levante, and parts of Catalonia and León—the remaining presence was a few scattered garrisons. Trying to hold a front line in an arc from Bilbao to Valencia, they were still vulnerable to assault, and had abandoned hopes of victory.

French prestige suffered another blow when on 17 March el rey intruso (the Intruder King, a nickname many Spanish had for King Joseph) left Madrid in the company of another vast caravan of refugees.