Second Battle of Porto During the ( Second ) Battle of Porto , also known as the Battle of the Douro , General Arthur Wellesley ' s Anglo - Portuguese Army defeated Marshal Nicolas Soult ' s French troops on 12 May 1809 and took the city of Porto . After taking command of the British troops in Portugal on 22 April Wellesley ( later named 1st Duke of Wellington ) immediately advanced on Porto and made a surprise crossing of the Douro River , approaching Porto where its defences were weak . Soult ' s late attempts to muster a defence were in vain . The French quickly abandoned the city in a disorderly retreat . This battle ended the second French invasion of Portugal . Soult soon found his retreat route to the east blocked and was forced to destroy his guns and burn his baggage train . Wellesley pursued the French army , but Soult ' s army escaped annihilation by fleeing through the mountains . Background . French occupation . In the First Battle of Porto ( 28 March 1809 ) , the French under General Soult defeated the Portuguese under Generals Lima Barreto and Parreiras outside the city of Porto . After winning the battle , Soult stormed the city . In addition to 8 , 000 military casualties , large numbers of civilians died . While Soult was in Porto , a detached force operated to the east under the leadership of Major - General Louis Loison . Initially , this force included General of Division Henri Delaborde ' s infantry division and Lorge ' s cavalry division . A Portuguese force under Major General Francisco Silveira captured the French garrison of Chaves and blocked Soult ' s communications with Spain by blockading the area around Amarante . From 18 April to 3 May , the Portuguese held Loison on the west bank of the Tâmega River . On the latter day , French engineers succeeded in disarming the explosives - rigged bridge so that Delaborde ' s infantry could cross it . By May , the French Marshal feared he was outnumbered by the English . Soult stayed up late on 11 May drawing - up his plans for retreat . General of Division Julien Augustin Joseph Mermet ' s division had already been sent off with the baggage and the artillery park . Soult retained a total of 10 , 000 infantry and 1 , 200 cavalry . Delaborde ' s division included three battalions each of the 17th Light , 70th Line , and 86th Line Infantry Regiments . General of Division Pierre Hugues Victoire Merle ' s division was composed of four battalions each of the 2nd and 4th Light Infantry Regiments , and three battalions of the 36th Line Infantry Regiment . General of Division Jean Baptiste Marie Franceschi - Delonne ' s cavalry was made up of the 1st Hussar Regiment , 8th Dragoon Regiment , and the 22nd and Hanoverian Chasseurs à Cheval Regiments . Anglo - Portuguese advance . After coming up from Lisbon , the Anglo - Portuguese fought a skirmish with the French at the Battle of Grijó on 11 May . Arriving at the Douro , Wellesley was unable to cross the river because Soult ' s army had either destroyed or moved all the boats to the northern bank . According to one historian , 20 , 000 men at Wellesley ' s command were organised thus : There were four 6 - gun artillery batteries ( RA : Sillery , Lawson . KGL : Tieling , Heise ) under Colonel ( Col ) Edward Howorth . One had 9 pounders , two had 6 pounders and one had 3 pounders . Historian Michael Glover stated that the order of battle was somewhat different . Glover lists the following organization . Farther to the east , William Carr Beresford ( Marshal of the Portuguese army ) led MG Christopher Tilson ' s British 3rd brigade ( 1 , 659 British and ca . 600 Portuguese grenadiers by 6 May morning state ) and 5 , 000 Portuguese to link up with Silveira ' s force . MG Alex Randoll Mackenzie ' s British 2nd brigade and a large Portuguese force operated on the line of the Tagus river . Action . On the morning of 12 May , Col John Waters was reconnoitring the river east of Porto . He was approached by a Portuguese barber who led him to a point on the bank hidden by brush where there was a skiff , a prior of the convent and three or four peasants . Partly at Waters ' entreaties and partly at the urging of the Prior , the peasants got into the skiff with the British officer and crossed the 500 - yard wide river , bringing back four unguarded wine barges from the opposite bank . When informed of this opportunity , Wellesley told them to let the men across . Immediately , a company of the 3rd Foot crossed the river and occupied a walled seminary overlooking the landing site . By the time the French realized that Wellesley ' s forces were on the north bank , the entire battalion of the " Buffs " of Hill ' s brigade had already been sent into the seminary . Soult , who was asleep at the time , remained unaware of these developments . General of Brigade Maximilien Foy , who was the first to see the British crossing , requisitioned three battalions of the 17th Light Infantry and led an attack on the seminary around 11 : 30 am . Foy was wounded and his soldiers beaten back with heavy losses . Reinforced later in the day by three more battalions , the French attacked again . By this time , however , three more battalions had occupied the seminary and surrounding buildings , and the French were defeated once again . Soult withdrew the troops guarding the Porto boats in order to reinforce Foy . As soon as the French left the riverside , the people of Porto immediately set out in " anything that would float " and ferried more British troops over . Four British battalions crossed immediately and attacked the French from the rear . The French , already planning a leisurely evacuation of the city , instead fled precipitously northeastward . In order to cut off the French retreat , MG John Murray ' s 2 , 900 - man brigade with the 14th Light Dragoons had been sent across the Douro at a ferry five miles to the east of Porto . Murray stood aside and failed to block the French escape route , though there was a skirmish . The 14th , however , sped after the retreating French . They charged and succeeded in cutting off about 300 Frenchmen , securing many of them as prisoners . Out of 110 horsemen , 35 were killed in this action . The British lost 125 men . In the battle for the seminary , Wellesley ' s second - in - command , Maj - Gen Edward Paget had his arm shattered by a French bullet and it had to be amputated . The French suffered 1800 casualties . Another source says the French suffered only 600 casualties . Foy was wounded . Soult ' s retreat . Due to Murray ' s error of judgement and the bulk of Wellesley ' s army being on the south side of the Douro , the French escaped on 12 May . However , Loison failed to clear Silveira ' s force away from Soult ' s planned path of retreat to the northeast , so Soult was compelled to abandon all his equipment and take footpaths over the hills to the north . Soult ' s and Loison ' s forces met at Guimarães , but Wellesley ' s army marched north . The British reached Braga ( northwest of Guimarães ) before the French , forcing Soult to retreat to the northeast again . Meanwhile , Beresford and Silveira were manoeuvring to block Soult ' s escape route in that direction . After escaping from several tight spots , Soult slipped away over the mountains to Orense in Spain . During the retreat , Soult ' s corps lost 4 , 500 men , its military chest and all 58 guns and baggage . In fiction . The battle of Porto is depicted by Bernard Cornwell in " Sharpe ' s Havoc " , Simon Scarrow in " Fire and Sword " , Allan Mallinson in " An Act of Courage " and by Iain Gale in " Keane ' s Company " .