The area astride the Spanish/Portuguese border between the respective fortresses of Ciudad Rodrigo and Almeida was the focus of the Peninsular War for much of the period from the autumn of 1809 through until 1812. The fortress of Ciudad Rodrigo that dominated the country between the Rivers Agueda and C a, was one of the 'Keys to Spain' for any army attacking either east or west across the frontier.With the defeat of the Fifth Coalition at Wagram in 1809, Napoleon was free to turn his attention to the rebellious Iberian Peninsula and the small British Army. Tasking a reluctant Marshal Mass na to 'throw the leopard into sea', preparations started for what proved to be a protracted and lackluster siege. Marshal Ney, however, champed at the bit and wanted to press on with the invasion and despite an increasing tempo of outpost actions, such as the renowned affair at Barbra del Puerco, Napoleon in attempting to control events from Paris, insisted on an orderly siege.With the fall of Ciudad Rodrigo, Craufurd's Light Division remained covering the Army's frontage but after a superbly conducted withdrawal, Craufurd's judgement erred and he was force into a costly fighting withdrawal to the River C a. The British now fell back into Portugal but by Spring 1811 they were back and with Napoleon stripping troops from the Peninsular Wellington could prepare to invade Spain and besiege Ciudad RodrigoPreparations for the siege were almost complete in December 1811, when further troops were stripped from Marshal Marmont, an opportunity to presented itself for a lightening operation to take Ciudad Rodrigo in the 1812 siege, which was of very different character.
