Siege of Burgos At the Siege of Burgos , from 19 September to 21 October 1812 , the Anglo - Portuguese Army led by General Arthur Wellesley , Marquess of Wellington tried to capture the castle of Burgos from its French garrison under the command of General of Brigade Jean - Louis Dubreton . The French repulsed every attempt to seize the fortress , resulting in one of Wellington ' s rare withdrawals , as he went on to defeat the army sent to flank him at the Lines Of Torres Vedras , pursued them and then returned to complete the siege of Burgos and capture the city The siege took place during the Peninsular War , part of the Napoleonic Wars . Burgos is located about north of Madrid . After crushing Marshal Auguste Marmont ' s French army at the Battle of Salamanca in July 1812 , Wellington exploited his great victory by advancing on Madrid . After the disaster , King Joseph Bonaparte and Marshal Jean - Baptiste Jourdan retreated to Valencia where they sought refuge with Marshal Louis Gabriel Suchet . The magnitude of Wellington ' s triumph also compelled Marshal Nicolas Soult to evacuate Andalucia in the south and withdraw to Valencia . The combined armies of Soult and Joseph soon posed a serious menace to Wellington ' s grasp on Madrid . The recently defeated French army in the north also built up its strength . Wellington made plans to counter the southern French threat while hoping to quickly capture the strategically important Burgos position , which was an important French supply base . Instead , Dubreton led a masterful defense , thwarting Wellington ' s assaults time after time . The British commander ' s hopes were blasted when his attempts to contain the twin French counteroffensives failed . With large French relief armies approaching Burgos from the northeast and Madrid from the southeast , the British commander withdrew to the west , abandoning large areas of Spain that had been recently liberated . That fall , the French lost an opportunity to defeat Wellington ' s army . Nevertheless , during the withdrawal to Portugal the Anglo - Portuguese army lost many men to pursuing French cavalry and starvation . Background . Wellington ' s victory over Marshal Marmont at the Battle of Salamanca on 22 July 1812 gravely weakened the French position in Spain . Before the engagement , King Joseph had set out with 14 , 000 troops , intending to reinforce the marshal , who was unaware that help was on the way . On 25 July , Joseph received a report from the wounded Marmont which covered up the extent of the disaster . Soon , General of Division Clausel reported the true state of affairs . He wrote to the king , " armies usually suffer in morale after a setback , [ but ] it is hard to understand the extent of discouragement existing in this one . I cannot conceal that a very bad spirit prevails . Disorders and the most revolting excesses mark every stage of our retreat . " Joseph immediately withdrew toward Madrid . Desperate to salvage the situation , the king ordered Marshal Nicolas Soult to send help and to evacuate Andalucia , but the marshal refused . On 30 July , Wellington ' s army reached Valladolid , northwest of Madrid . Leaving 18 , 000 troops with Lieutenant General Henry Clinton to watch Clausel , the British army commander turned toward Madrid with 36 , 000 men . On 11 August , General of Division Anne - François - Charles Trelliard ' s dragoon division fought an inconclusive skirmish with the Allies at the Battle of Majadahonda northwest of Madrid . At first , the French dragoons routed Brigadier General Benjamin D ' Urban ' s Portuguese cavalry . After also driving back Major General George Bock ' s King ' s German Legion ( KGL ) heavy dragoons , the French were finally stopped by fire from the 1st KGL Light Infantry Battalion and the approach of heavy reinforcements . King Joseph evacuated Madrid which the Anglo - Portuguese entered on 12 August , to the cheers of the inhabitants . The following day , the Retiro forts surrendered to Wellington , yielding 2 , 046 prisoners , large stocks of clothing and equipment , and the eagles of the 13th Dragoon and the 51st Line Infantry Regiments . Harassed by guerillas and tortured by thirst , Joseph ' s soldiers retreated all the way to the east coast city of Valencia , which they reached on 31 August . Valencia was held by Marshal Louis Gabriel Suchet . Wellington knew that if Joseph and Soult joined forces , his position in central Spain would become perilous . He counted on the autumn rains keeping the Tagus River high and preventing Joseph and Soult from threatening his southern flank . He hoped that the Spanish might delay any French counterattack toward Madrid . He also believed that the capture of Burgos would slow any French drive from the north . To Wellington ' s amazement , Clausel quickly rallied his beaten army and launched a raid in the north . On 13 August , the French general marched on Valladolid with 25 , 000 troops . In the face of this advance , Clinton fell back to Arévalo with 7 , 000 soldiers while José María Santocildes ' s Spanish corps abandoned Valladolid . Clausel sent his lieutenant Maximilien Sebastien Foy to rescue the trapped French garrisons . While Astorga surrendered before he could reach it , Foy successfully relieved Toro and Zamora and reunited with Clausel at Valladolid on 4 September . Wellington and 21 , 000 troops rejoined Clinton at Arévalo on 3 September . The British army commander set out after Clausel , but that general easily shook off his pursuers and dashed out of reach , leaving a garrison of 2 , 000 men in Burgos . Wellington left Lieutenant General Rowland Hill to defend Madrid with 31 , 000 Anglo - Portuguese and 12 , 000 Spanish . This force included Wellington ' s three best divisions . Siege . San Miguel Hornwork . The 35 , 000 - man Anglo - Portuguese - Spanish army laid siege to the castle of Burgos on 19 September . General of Brigade Jean - Louis Dubreton commanded two battalions of the 34th Line Infantry Regiment , one battalion of the 130th Line , one artillery company , one sapper company , nine heavy cannons , 11 field pieces , and six mortars , altogether 2 , 000 troops . The inner Burgos defenses contained a stronghold known as the Napoleon Battery . Historians differ as to how many heavy guns Wellington had available . Michael Glover wrote that the British had only three 18 - pound cannon with 1 , 306 rounds . David Gates asserted that Wellington only brought eight siege guns though many more recently captured pieces were available . Chris McNab credited the British with having a total of eight 24 - pound guns . Admiral Sir Home Popham of the Royal Navy offered to land more heavy guns at Santander , but Wellington declined to use this resource . After costly assaults at the sieges of Ciudad Rodrigo and Badajoz , he was loath to mount a massive infantry attack . At the time , the British army ' s sapper corps , then called Military Artificers , was seriously understrength . At Burgos , there were only five engineer officers and eight sappers . During the siege operation , one of the sappers was killed and other seven were wounded . On the night of 19 September , Wellington ordered an assault on the San Miguel hornwork , which guarded the fort ' s northeast approaches . Launched without the benefit of artillery support , the 1st Battalion of the 42nd Foot was spotted by the French in the moonlight and over 200 men were mowed down . Brigadier General Denis Pack ' s Portuguese brigade suffered an additional 100 losses . Fortunately for the British , the flank companies of the 1st / 42nd Foot , 1st / 24th Foot , and 1st / 79th Foot were able to gain access to the rear of the hornwork . From there they opened a scattered fire on the French . The defenders suddenly stampeded , leaving the hornwork in the Allies ' possession . The 1st Battalion of the 34th Line lost 138 killed and wounded , plus 60 men and seven guns captured . Allied losses numbered 421 killed and wounded . Burgos Castle . Wellington quickly began planting batteries around the castle . But hoping to get lucky again , he launched an attack on 23 September before his guns were ready for action . The 1st and 6th Divisions rushed forward against the undamaged walls but were easily repelled with 200 men killed and wounded . The engineers then began digging a mine under the fort ' s west wall . When this was detonated on 29 September , the British dashed forward but were soon driven back from the intact defenses . It turned out that the mine was run under an ancient buried wall that was in front of the modern wall . Consequently , the French defenses were unscathed by the explosion . A frustrated Wellington ordered his engineers to dig a new mine . Meanwhile , he had his soldiers work overnight to erect a breaching battery close to the walls . At daybreak on 1 October , the French discovered this position and immediately zeroed in their defending artillery . They rapidly destroyed two of the three cannons and inflicted heavy losses on the gun crews . The following night the British reestablished the battery only to see it destroyed again in the morning . On 2 October , Wellington asked Popham to send two 24 - pound cannons to replace his lost artillery . As it happened , these guns would not arrive in time . When the new mine was finally ready on 4 October , it was fired , blowing a gap in the northwest wall . The subsequent attack managed to secure a foothold in the outer defenses after heavy fighting and 220 casualties . After the Allies began digging a new trench against the inner defenses , Dubreton launched a sortie without warning . The attackers killed and wounded almost 150 Allies and carried off or spoiled much of their equipment . No sooner had Wellington resumed siege operations than Dubreton struck again . With perfect timing , the French swarmed out of the fort and inflicted 184 casualties while suffering small losses . Rain began to fall in sheets , flooding the siege trenches . The British guns ran so low on ammunition that French cannonballs were retrieved and reused . Wellington wrote , " This is altogether the most difficult job I ever had in hand with such trifling means . God send that they may give me a little more time . " On 18 October , a mine was detonated under the Chapel of San Roman near the south wall . Under cover of this feint , assaults were mounted against the west and north walls . As before , these attacks withered in the face of intense fire and 170 more casualties were added to the butcher ' s bill . With a French army threatening his position , Wellington made preparations to retreat . However , he was unable to withdraw all his siege guns . The engineers tried to demolish the captured hornwork , but their charges failed to explode . British losses in the siege amounted to 550 killed , 1 , 550 wounded , and three guns . The French lost 304 killed and 323 wounded , plus the 60 captured . Operations . Soult raised the Siege of Cadiz on 25 August 1812 and abandoned a huge wagon train of booty in Seville on the 28th . By the end of September , Soult was in contact with Suchet and Joseph . On 15 October , Joseph ' s forces moved on Madrid with 61 , 000 soldiers and 84 guns . Soult ' s column was on the left while a second column under Jean - Baptiste Drouet , Comte d ' Erlon marched to Soult ' s right . In the north , General of Division Joseph Souham ' s 41 , 000 - man Army of Portugal was swollen to 53 , 000 by transferring 6 , 500 infantry and 2 , 300 cavalry from the Army of the North and by 3 , 400 reinforcements from France . To hold off these heavy concentrations , Wellington deployed 73 , 000 troops . At Burgos , he had 24 , 000 Anglo - Portuguese and Santocildes ' 11 , 000 Spaniards . In the south Hill occupied Toledo with 20 , 000 soldiers while Major General Charles Alten held Madrid with 18 , 000 . Angry that Wellington had been offered the supreme command in Spain , General Francisco Ballesteros refused to obey the British general ' s orders to obstruct Soult ' s move . High hopes had been placed on 8 , 000 Anglo - Sicilians under Lieutenant General Thomas Maitland at Alicante on the east coast . Maitland remained completely inert during this crisis . Wellington was north of Madrid at Burgos , dangerously separated from Hill ' s army . To make matters worse , the Tagus was not a serious military obstacle because of unexpectedly low water . When Wellington realized how badly he was outnumbered by Souham , he felt lucky to get away intact . He later wrote , " I had no reason to believe the enemy were so strong till I saw them . Fortunately , they did not attack me : if they had , I must have been destroyed . " Even so , he was loath to undertake a long retreat . Aftermath . Wellington raised the siege of Burgos on 21 October . He quietly slipped away , undetected by the French until late on 22 October . The drawn Battle of Venta del Pozo was fought on the 23rd . The bulk of the Allied army fell back behind the Pisuerga River at Torquemada that day . Between 25 and 29 October , Souham and Wellington fought a series of actions along the Pisuerga and Carrión Rivers at Palencia , Villamuriel de Cerrato , and Tordesillas which are collectively called the Battle of Tordesillas . When the French seized the bridge over the Duero River at Tordesillas on the 29th , Wellington was compelled to order a retreat . On 29 October , Hill received Wellington ' s positive order to abandon Madrid and march to join him . After a clash with Soult ' s advance guard at Perales de Tajuña on the 30th , Hill broke contact and withdrew in the direction of Alba de Tormes . Joseph re - entered his capital on 2 November . Anxious to destroy the British , Joseph rushed after them without bothering to leave a garrison in Madrid . The Allied retreat continued until Wellington and Hill joined forces on 8 November near Alba de Tormes . On 15 November , Soult ' s 80 , 000 Frenchmen faced Wellington ' s 65 , 000 Allies on the old Salamanca battlefield . To the disappointment of many French soldiers and generals , Soult declined to attack . Wellington began retiring west that afternoon . Logistical arrangements in Wellington ' s army collapsed and the Allied soldiers marched in cold pouring rain for four days with very little food . Soult only sent his cavalry after the Allies . Even so , the French horsemen scooped up hundreds of stragglers . On 16 November , 600 Allied soldiers were captured by the French . The number of prisoners was even higher on the 17th and included Wellington ' s second - in - command , General Edward Paget . Before reaching the friendly fortress of Ciudad Rodrigo , the Allied armies lost 5 , 000 men missing , mostly soldiers who had died from hunger or exposure in the chaotic retreat . It appeared that all of Wellington ' s efforts in 1812 had been for nothing . Yet , his Anglo - Portuguese army had gained a moral ascendancy over the French that it would never relinquish .