Battle of Abensberg The Battle of Abensberg took place on 20 April 1809 , between a Franco - German force under the command of Emperor Napoleon I of France and a reinforced Austrian corps led by Feldmarschall - Leutnant Archduke Louis of Austria . As the day wore on , Feldmarschall - Leutnant Johann von Hiller arrived with reinforcements to take command of the three corps that formed the Austrian left wing . The action ended in a complete Franco - German victory . The battlefield was southeast of Abensberg and included clashes at Offenstetten , Biburg - Siegenburg , Rohr in Niederbayern , and Rottenburg an der Laaber . On the same day , the French garrison of Regensburg capitulated . After Marshal Louis - Nicolas Davout ' s hard - fought victory at Battle of Teugen - Hausen the previous day , Napoleon determined to break through the Austrian defenses behind the Abens River . The emperor assembled a provisional corps consisting of part of Davout ' s corps plus cavalry and gave Marshal Jean Lannes command over it . Napoleon directed his German allies from the Kingdom of Bavaria and the Kingdom of Württemberg to attack across the Abens from the west , while Lannes thrust from the north toward Rohr . While the Austrians initially held the river line , Lannes ' strike force crashed through Louis ' defenses farther east . On the left , the Austrians managed to conduct a capable rear guard action , but during the day the French smashed their opponents ' right flank and captured thousands of soldiers . The day ended with the Austrians barely holding onto a line behind the Große Laber River . The next day , Hiller withdrew to Landshut , separating the left wing from the main army under Generalissimo Archduke Charles , Duke of Teschen near Regensburg ( Ratisbon ) . The French surrender of Regensburg on 20 April allowed Charles ' army a retreat route to the north bank of the Danube . The Battle of Landshut was fought on 21 April . Background . Operations . Archduke Charles stole a march on Napoleon when his army invaded the Kingdom of Bavaria on 10 April 1809 . Even though the Austrian army took six days to slowly march from the Inn River at the frontier to the Isar River , the move placed the army of France and their German allies in grave danger . Napoleon ' s deputy commander , Marshal Louis Alexandre Berthier mismanaged the Grande Armée ' s concentration , leaving its units scattered across a broad front in a confused state . The central mass of Archduke Charles ' 209 , 600 - man host crossed the Isar at Landshut on 16 April , but the next day Emperor Napoleon arrived at the front from Paris . Desperately trying to wrest the initiative back from the archduke , Napoleon consolidated his forces and ordered Marshal André Masséna ' s IV Corps and General of Division Nicolas Oudinot ' s II Corps on the right flank to march on Landshut to cut the Austrian line of communications . He planned for Marshal François Joseph Lefebvre ' s Bavarian VII Corps to hold in the center at Abensberg while Davout ' s left flank III Corps withdrew west to escape being trapped between Charles ' main body and the Danube . On 19 April , Charles realized he had an opportunity to destroy Davout . He launched 65 , 000 troops in three powerful columns northwest as Davout attempted a flank march across his front . Luckily for the French , General of Cavalry Johann I Joseph , Prince of Liechtenstein ' s 20 , 000 troops found no opposition on the Austrian right . In the center , General of Division Louis - Pierre Montbrun ' s 3 , 800 cavalry and infantry skilfully held off Feldmarschall - Leutnant Prince Franz Seraph of Rosenberg - Orsini ' s much stronger IV Armeekorps for most of the day . On the left flank , Feldmarschall - Leutnant Prince Friedrich Franz Xaver of Hohenzollern - Hechingen ' s III Armeekorps crashed into General of Division Louis Vincent Le Blond de Saint - Hilaire ' s division and a terrific fight blazed up . Both sides fed in reinforcements as the infantry battled over a pair of parallel ridges in the Battle of Teugen - Hausen . Ultimately , Davout brought superior forces to bear in the late afternoon and pushed back the Austrians a short ways . That night , Charles ordered Hohenzollern to withdraw a little to the east , closer to his main body . On the morning of 19 April , Archduke Charles requested that Hohenzollern provide a link between the III and V Armeekorps . Accordingly , the III Armeekorps commander detached General - Major Ludwig Thierry ' s 6 , 000 - man infantry brigade to his left . As an additional link between Thierry and III Armeekorps , Hohenzollern detached General - Major Joseph Freiherr von Pfanzelter with a Grenz infantry battalion and two squadrons of hussars , about 1 , 000 men . While the Battle of Teugen - Hausen raged , Thierry clashed with Bavarian troops near Arnhofen and fell back to Offenstetten . Austrian deployment . On 20 April , Archduke Charles ' main body consisted of the III , IV , and I Reserve Armeekorps . These were arrayed near Dünzling and Eckmühl . Feldzeugmeister Johann Kollowrat ' s II Armeekorps spent 19 April attacking Regensburg from north of the Danube . While successfully defending the city , Colonel Louis Coutard ' s 2 , 000 - man 65th Line Infantry Regiment ran dangerously low on small - arms ammunition . General of Cavalry Count Heinrich von Bellegarde ' s I Armeekorps also remained north of the Danube . Archduke Louis spread out his V Armeekorps behind the Abens River , facing west . Having detached Feldmarschall - Leutnant Karl Friedrich von Lindenau ' s division to Liechtenstein , only the divisions of Feldmarschall - Leutnants Prince Heinrich XV of Reuss - Plauen and Vincenz Freiherr von Schustekh - Herve remained under Louis ' command . Feldmarschall - Leutnant Michael von Kienmayer ' s II Reserve Armeekorps , nominally 7 , 975 - strong , waited in support at Ludmannsdorf . Kienmayer ' s cuirassier brigade under General - Major Andreas von Schneller was serving with Liechtenstein and four dragoon squadrons were attached to Thierry ' s brigade . On the evening of the 19th , the bulk of Hiller ' s VI Armeekorps reached Mainburg to the south . Like V and II Reserve Armeekorps , the VI suffered from detachments . At the beginning of the war , Charles sent the division of Feldmarschall - Leutnant Franz Jellacic to hold Munich , the Bavarian capital , where it remained . Hiller also posted General - Major Armand von Nordmann with a small force at Moosburg an der Isar to watch his south flank . The official returns of Hiller ' s three corps totalled 75 , 880 troops , but after detachments , the left wing numbered only 42 , 000 . French deployment . When Lannes arrived at the front , Napoleon immediately placed him in command of a provisional corps . This ad hoc formation consisted largely of III Corps units that escaped Archduke Charles ' trap the day before , namely General of Division Charles Antoine Morand ' s 1st Division , General of Division Charles - Étienne Gudin de La Sablonnière ' s 3rd Division , General of Division Raymond - Gaspard de Bonardi de Saint - Sulpice ' s 2nd Heavy Cavalry Division , and General of Brigade Charles Claude Jacquinot ' s light cavalry brigade of Montbrun ' s division . Also added was General of Division Etienne Marie Antoine Champion de Nansouty ' s 1st Heavy Cavalry Division from the cavalry reserve . One of Saint - Sulpice ' s brigades was detailed to guard Saal an der Donau , a defile between Lannes and Davout . On the morning of 20 April , Napoleon mistakenly assumed that the bulk of Archduke Charles ' army lay in front of him . Accordingly , he gave orders for a drive southeast in the direction of Landshut . Lannes ' mission was to turn the Austrian right flank by pushing south toward Rohr . General of Division Dominique Vandamme would attack Siegenburg with his small Kingdom of Württemberg corps . Lefebvre ' s other VII Corps divisions , together with General of Division Joseph Laurent Demont ' s Reserve Division of the III Corps , would link Lannes and Vandamme . Napoleon ordered Masséna ' s IV Corps to capture Landshut and the Isar River crossings , cutting the Austrian line of communications . Battle . Abensberg . Archduke Charles sent orders to his brother Archduke Louis at 7 : 30 AM on 20 April . He instructed Louis to fall back to Rottenburg and defend behind the Große Laber . Charles intended Hiller to take position on Louis ' left at Pfeffenhausen . Charles erred in sending the orders so late and in not informing Louis of Hohenzollern ' s withdrawal to the east . The latter move left the V Armeekorps ' right flank exposed . Pfanzelter held Bachl on the extreme right flank . To the west of Bachl , Thierry held Offenstetten with three and one - third battalions . His other two and two - thirds battalions had become separated the previous day and joined General - Major Frederick Bianchi , Duke of Casalanza who had six battalions near Biburg . Louis posted Schustekh with four squadrons of hussars and one and one - third battalions at Rohr . Schustekh ' s infantry had just rejoined V Armeekorps after marching from Mainburg with General - Major Joseph , Baron von Mesko de Felsö - Kubiny ' s detachment . In one account , Lannes ' advance guard approached Bachl in the late morning of 20 April , forcing Pfanzelter ’ s small detachment from the Austrian III Armeekorps eastward . The 1st Bavarian Division under Lieutenant General Crown Prince Ludwig of Bavaria and the 3rd Bavarian Division led by Lieutenant General Bernhard Erasmus von Deroy , together with Demont ’ s III Corps Division advanced on Offenstetten . Around 10 : 00 AM , they defeated Thierry ’ s brigade , forcing him back on Bachl as Lannes approached from the north . Thierry hastily withdrew to Rohr , which he reached at 2 : 00 PM . Historian James R . Arnold offers a different narrative . He writes that Pfanzelter ' s command was withdrawn on the III Armeekorps commander Hohenzollern ' s orders , leaving the north - south road through Bachl wide open . Meanwhile , Thierry ' s attached dragoons discovered that Abensberg and its nearby roads were alive with moving columns of enemy troops . Around 8 : 00 AM , Thierry fell back on Bachl and found to his dismay that French cavalry already occupied the village . Having become separated from his supporting dragoons , Thierry ' s men were chased into the woods by Jacquinot ' s horsemen . From there the Austrians hiked cross - country toward Rohr . Author Francis Loraine Petre states that Gudin encountered Pfanzelter north of Bachl and brushed him aside about 9 : 00 AM . The 1st Bavarian division and General - Major Hügel ' s Württemberg brigade drove Thierry from Offenstetten around 10 : 00 AM . When the Austrians reached Bachl they stumbled upon Jacquinot who attacked and they " scattered through the woods " . Pfanzelter marched east to Langquaid where he rejoined Hohenzollern ' s corps . Because he feared that the woods to his left might contain Austrians , Lannes slowed his march so he could scout the terrain to the east . Even so , his column arrived at Rohr before Thierry ' s infantry . Without Pfanzelter ' s detachment to warn him , the arrival of Lannes ' column surprised Schustekh . The Austrian commander gamely threw four squadrons of hussars at Jacquinot ' s advance guard . Eventually , Jacquinot got his entire brigade into action and pressed the Austrian hussars back on the supporting battalion and one - third of Grenz infantry south of Rohr . At this time , Thierry ' s winded infantry appeared on the scene . With the help of Gudin ' s 17th Light Infantry and a battery of artillery , Jacquinot ' s chasseurs broke Thierry ' s foot soldiers and hounded them into the woods again . To take the pressure off the infantry , Schustekh charged again , just as Thierry ' s lost dragoons showed up . At first , the attack went well , but then the Austrian horsemen came up against a mass of cuirassiers . The result was a rout of the Habsburg cavalry , who rode through the ranks of their own foot soldiers . The French chasseurs and cuirassiers rode roughshod over the troops of Thierry and Mesko , cutting down the fugitives . Over 3 , 000 Austrians became prisoners , including Thierry , and four cannon were lost . The previous evening , Hiller ' s VI Armeekorps bivouacked at Mainburg . Though a road ran directly from Mainburg to Louis ' left flank at Siegenburg , a distance of only 13 kilometers , Hiller elected to join his colleague by a roundabout march via Pfeffenhausen . Once he arrived , Hiller was authorized to take command of all three left wing corps . Hiller personally arrived in Siegenburg to confer with Archduke Louis around midday . Hearing troubling reports from the right flank , he sent Feldmarschall - Leutnant Karl von Vincent toward Rottenburg with the line brigades of Generals - Major Josef Hoffmeister and Nikolaus Weissenwolf , plus four squadrons of the " Rosenberg " Chevauxlegers Regiment # 6 . Archduke Louis posted Prince Reuss and General - Major Joseph Radetzky von Radetz with four battalions and 12 cavalry squadrons at Siegenburg . Bianchi held the east bank of the Abens opposite Biburg . Lieutenant - General Karl Philipp von Wrede probed at Siegenburg but his 2nd Bavarian Division was easily fended off by Radetzky and a battery of 12 - pdr cannon . At this time , Louis heard that the French attacked Thierry , so he ordered Radetzky to send two battalions to the right flank and called up Kienmayer ' s command from Ludmannsdorf . Wrede moved north to Biburg , where he tried to get across the Abens again . At first he was not successful , but Bianchi withdrew to Kirchdorf , allowing the 2nd Bavarian Division to cross to the east bank of the stream . Meanwhile , General of Division Dominique Vandamme ' s Württemberg contingent ( later known as the VIII Corps ) replaced Wrede in front of Siegenburg . Vandamme soon realized that crossing at Siegenburg was futile , so he too marched north , crossed the river at Abensberg and moved south to Kirchdorf . Here the Bavarians and Württembergers found Bianchi with his reinforced brigade and a cavalry squadron . Reuss soon arrived with Radetzky ' s two battalions . Around 2 : 00 PM a sharp combat took place after which the Austrians retreated to the southeast . According to one account , General of Division Jean Victor Tharreau ' s cavalry of the II Corps also became involved at Kirchdorf . Pressed by Wrede ' s 7th Bavarian Infantry Regiment , plus two of Hügel ' s Württemberg battalions , Radetzky conducted an orderly retreat on the Siegenburg road , covered by the grenzers and Kienmayer ' s grenadiers under General - Major Konstantin Ghilian Karl d ' Aspré . He managed to shepherd the V Armeekorps trains safely through Pfeffenhausen before the Bavarians cut him off . Wrede pursued aggressively and scooped up many prisoners but failed to capture the bridge , which the Austrians burned . Even so , the Bavarians kept up the pressure , crossing the shallow Große Laber at 11 : 00 PM to attack . Radetzky fell back to a hill called the Hornbach where his rear guard skirmished with the Bavarians into the early morning hours . When Vincent ' s column neared Rottenburg , he found the road jammed with the III Armeekorps trains . A charge by the " Rosenberg " Chevauxlegers halted the French cuirassiers long enough for his infantry to gain solid positions on the east side of the Große Laber . Hiller arrived at Rottenburg in the late afternoon and ordered a counterattack at 7 : 00 PM . Vincent swung his left brigade forward and quickly overran a Bavarian unit , capturing 300 troops . Soon after , the " Deutschmeister " Infantry Regiment # 4 got into a vicious firefight with Bavarian and French infantry . In the twilight , the Austrians were forced back by superior numbers with 600 casualties , but they had finally stopped their enemies . Regensburg . On 20 April , the Austrian II Armeekorps continued attacking Colonel Louis Coutard ' s 65th Line Infantry Regiment at Regensburg . A French convoy sent to replenish the critically low ammunition supply was ambushed by Austrian cavalry at 8 : 00 AM . The French troops finally ran out of ammunition and Coutard asked Kollowrat for a 24 - hour truce after which he promised to surrender if not relieved . The Austrian commander foolishly agreed to the terms . However , Liechtenstein ' s column soon appeared from the south . Liechtenstein pointed out that the existing truce did not apply to him and demanded an immediate surrender . Coutard thereupon capitulated at 5 : 00 PM . The French sappers had found it impossible to demolish the sturdily - built Regensburg bridge . The intact bridge later played a key factor in the escape of Charles ' army . In two days of fighting , the French lost 11 officers and about 200 soldiers killed and wounded , plus 1 , 988 captured . Austrian losses were 73 dead , 220 wounded , and 85 missing for a total of 378 casualties . During the struggle the French captured 75 troops and one color , all of which were recovered . When Kollowrat finally reported the II Armeekorps available for duty that evening , the headquarters ordered his troops to make an overnight march west to Hemau on the north bank of the Danube . In the morning , the tired troops were recalled to Regensburg from their pointless ramble . Aftermath . Arnold lists 1 , 107 Allied casualties , including 746 Bavarians . He gives Austrian losses as 492 killed , 2 , 219 wounded , and nearly 4 , 000 captured , or a total of 6 , 711 . The French also captured eight colors and 12 cannons . Digby Smith notes Allied casualties as 34 dead and 438 wounded , but this seems to count only the German allied troops . Austrian total losses are given as 6 , 872 , including 3 , 000 to 4 , 000 captured . The 2nd battalion of the " Broder " Grenz ( Mesko ' s brigade ) was annihilated , with 18 officers and 1 , 040 rank and file counted as lost . Petre lists 2 , 710 Austrians killed and wounded , plus about 4 , 000 captured . Altogether , the 42 , 000 troops of Hiller ' s three - corps left wing faced 55 , 000 French and their German allies . Only about 25 , 000 Austrians and an equal number of Allies were engaged in action . That evening , as the extent of Thierry and Schustekh ' s disaster became known , Hiller resolved to pull his three corps behind the Isar at Landshut . In this decision , he was also influenced by Masséna ' s move against his left rear and unfavorable reports from Archduke Louis . This crucial decision meant that the Austrian left wing would in the near future operate independently from Archduke Charles ' main body . Hiller would only reunite with his army commander on 15 May north of Vienna . While Napoleon savaged his left wing , Archduke Charles remained amazingly inert . At 6 : 00 AM , the archduke was with Prince Rosenberg and at 7 : 30 AM he sent orders to Archduke Louis and then wrote a letter to Emperor Francis I of Austria . But from 11 : 00 AM until 6 : 30 PM , the Austrian generalissimo failed to issue any orders . He either became obsessed with capturing Regensburg or he had an epileptic seizure during which he is supposed to have locked himself in his quarters . The epileptic attack is probable , but there is a possibility it may be a cover story for Charles ' failure to exercise command . What is known is that the Austrian III , IV , and I Reserve Armeekorps did not disturb Davout ' s remaining three divisions under Generals of Division Louis Friant , Saint - Hilaire , and Montbrun on 20 April . Despite being outnumbered , Napoleon ' s 113 , 000 troops split the 161 , 000 strung - out Austrians into two forces . Charles five corps , including 48 , 000 additional troops of the I and II Armeekorps north of Regensburg , lay to the north while Hiller ' s three corps fell back to Landshut . ( Massena and Oudinot ' s 57 , 000 soldiers are not counted in Napoleon ' s total . ) Both Austrian forces had to fight a second major battle each . Hiller fought the Battle of Landshut on 21 April , while Charles engaged in the Battle of Eckmühl on the 22nd . Order of battle . " The following is an abbreviated order of battle . Complete orders of battle are found in the Abensberg 1809 Order of Battle . " Austrian forces . Left Wing : Feldmarschall - Leutnant Johann von Hiller French - Allied forces . Grande Armée : Napoleon I of France