Battle of Alcantara ( 1809 ) The Battle of Alcantara ( 14 May 1809 ) saw an Imperial French division led by Marshal Claude Perrin Victor attack a Portuguese detachment under Colonel William Mayne . After a three hours skirmish , the French stormed across the Alcántara Bridge and forced the Portuguese to retreat . The clash happened during the Peninsular War , part of the Napoleonic Wars . Alcántara , Spain is situated on the Tagus river near the Portuguese border , west - southwest of Madrid . While Marshal Nicolas Soult invaded northern Portugal in early 1809 , two other French forces stood ready to cooperate in the subjugation of Portugal . Pierre Belon Lapisse ' s division lurked near Ciudad Rodrigo while Victor ' s I Corps operated in the Tagus valley . A weak force under Robert Thomas Wilson watched Lapisse while Alexander Randoll Mackenzie ' s Anglo - Portuguese corps kept an eye on Victor . After being outgeneraled by Wilson , Lapisse marched south to join Victor . As Sir Arthur Wellesley ' s Anglo - Portuguese army disposed of Soult ' s corps , the detachment under Mayne moved to occupy Alcántara . Believing Mayne ' s troops to be a serious threat , Victor marched against him . The Loyal Lusitanian Legion battalion stoutly defended the Alcántara Bridge for three hours . Then , the French artillery silenced their guns and a supporting battalion of militia took to its heels . The bridge was mined , but when Mayne ordered the charges to be detonated , its heavy construction withstood the explosion . Victor ' s infantry then rushed the incompletely demolished span . The French hung around the area for a few days but finally withdrew . The next action was the Battle of Talavera . Background . Emperor Napoleon ' s strategy for early 1809 called for an invasion of Portugal by three columns . He ordered Marshal Nicolas Soult ' s 20 , 000 troops to advance from the north , General of Division Pierre Belon Lapisse ' s 9 , 000 men to come in from the east , and Marshal Claude Perrin Victor ' s soldiers to march from the south . Napoleon ' s plan called for Soult to capture Porto ( Oporto ) by 5 February 1809 . From there , Soult was supposed to march to Lisbon and occupy it by the 16th of the same month . Meanwhile , Lapisse was directed to move from Salamanca to seize Ciudad Rodrigo and Almeida , Portugal as soon as Soult ' s II Corps got to Porto . Victor was ordered to be at Mérida by this time . He was instructed to detach a column from there to advance on Lisbon . The emperor assumed that Soult , Lapisse , and Victor would be easily able to send messengers to each other , and easily coordinate their operations . This assumption ignored the likelihood that Portuguese and Spanish guerillas would prevent Soult ' s dispatches from reaching his colleagues . Soult marched south on 30 January 1809 , aiming for Portugal . After being repelled in his initial attempt to cross the Minho River in mid - February , his forces marched to Ourense and crossed the bridge there . Soult ' s cavalry crushed a Spanish brigade at La Trepa on 6 March and the II Corps entered Portugal on the 9th . At the Battle of Braga ( 1809 ) on 20 March , the French routed a Portuguese army consisting of a few regulars and 22 , 000 militia . The First Battle of Porto on the 29th was another lopsided French victory marked by terrible Portuguese loss of life . But despite being established in Porto , Soult found his communications cut by General Silveira ' s regular and irregular forces and he had no idea of the whereabouts of Lapisse . Meanwhile , Marshal Victor won a resounding victory over General Gregorio García de la Cuesta ' s Spanish army at the Battle of Medellín on 28 March 1809 . Though he went on to occupy Mérida , Victor complained in dispatches to King Joseph Bonaparte that he lacked the strength to invade Portugal . He requested the return of Lapisse ' s division , but was refused . Forces . An Anglo - Portuguese force under Major General Alexander Randoll Mackenzie watched the Portuguese frontier , based at Abrantes . The British element of this force included Brigadier General Henry Fane ' s 1 , 304 - saber British cavalry brigade , Mackenzie ' s 2 , 709 - man British infantry brigade , and May ' s 315 - strong Royal Artillery battery . The 3rd Dragoon Guards and the 4th Dragoons were the mounted units while the 2nd Battalion of the 24th Foot , 3rd Battalion of the 27th Foot , 2nd Battalion of the 31st Foot , and the 1st Battalion of the 41st Foot were the infantry . The Portuguese contingent consisted of a cavalry brigade , an infantry brigade , and two artillery batteries . Five squadrons of the 3rd and 4th Dragoons made up the cavalry brigade . The infantry brigade comprised the 1st and 2nd Battalions of the 3rd , 4th , 13th , and 15th Line Regiments , the 1st Battalion of the 1st Regiment , and the 1st , 4th , and 5th Caçadores Battalions . Battle . Wellington ordered Colonel William Mayne ' s 1st Battalion of the Loyal Lusitanian Legion , the " Idanha " Militia Battalion , and six Legion guns to serve as an outpost to Mackenzie ' s corps . The approximately 2 , 000 Portuguese came down from the mountains to the north and moved into Alcántara . Believing that Mayne ' s detachment was the spearhead of an offensive , Victor set out on 11 May to deal with the presumed threat . The division with Victor was commanded by Lapisse . The 2nd Division of the I Corps consisted of three battalions each of the 16th Light Infantry Regiment and the 8th , 45th , and 54th Line Infantry Regiments . Including eight squadrons in one brigade of dragoons , Victor ' s force numbered 9 , 500 men and 12 guns . The horsemen belonged to General of Division Marie Victor de Fay , marquis de Latour - Maubourg ' s 1st Dragoon Division , which consisted of the 1st , 2nd , 4th , 9th , 14th , and 26th Dragoons . One authority wrote that Mayne ' s total of 1 , 850 men included one squadron of Legion cavalry and only two artillery pieces .