On 11 October 1810, Marshal
André Masséna's French army found itself confronted by the elaborately built and well-defended
Lines of Torres Vedras in its invasion of Portugal. Foiled by the virtually impregnable defenses, the French commander halted to wait for reinforcements. Unable to secure enough food, the French army wasted away from starvation and illness. By 1 January 1811, the 65,000-strong army had shrunk to 46,500. Massena reluctantly retreated from Portugal beginning on 6 March. The British army of
Viscount Wellington beat the French
II Corps of
General of Division Jean Reynier at the
Battle of Sabugal on 3 April 1811. The next day, the British invested the fortress of Almeida. After Marshal
André Masséna's retreat from Portugal, the French installed a garrison of 1,400 men under Brenier in the fortress. These troops were blockaded in the town by forces under
Arthur Wellesley, 1st Duke of Wellington. Since the
Anglo-Portuguese Army had no heavy guns to breach the walls, they were forced to starve the garrison out. Because of this, this operation was technically a
blockade rather than a
siege. From 3 to 5 May 1811, Masséna failed to relieve Almeida in the
Battle of Fuentes de Oñoro. During this time, the blockade was maintained by
Major General William Erskine's 5th and Major General
Alexander Campbell's 6th Divisions, plus Count Barbacena's 300-man Portuguese cavalry brigade. Campbell guarded the south and west sides of the fortress with too many soldiers and placed his men too far from the city. Though instructed by Wellington to block the Barba del Puerco bridge on the afternoon of the 10th, Erskine neglected to forward the necessary orders in time. ==Escape==