Battle of Eckmühl The Battle of Eckmühl ( also known as " Eggmühl " ) fought on 21 April – 22 April 1809 , was the turning point of the 1809 Campaign , also known as the War of the Fifth Coalition . Napoleon I had been unprepared for the start of hostilities on 10 April 1809 , by the Austrians under the Archduke Charles of Austria and for the first time since assuming the French Imperial Crown had been forced to cede the strategic initiative to an opponent . Thanks to the dogged defense waged by the III Corps , commanded by Marshal Davout , and the Bavarian VII Corps , commanded by Marshal Lefebvre , Napoleon was able to defeat the principal Austrian army and wrest the strategic initiative for the remainder of the war . Strategic situation . Operating over a fifty mile front , from Ratisbon to Pfaffenhofen ( district ) , marked by stretches of rugged , wooded terrain , neither the French nor the Austrians had developed adequate intelligence about their opponent ' s strength , dispositions or intentions . Assuming that the bulk of the Austrian army was deployed so as to cover their bridgehead at Landshut and the main highway to Vienna , on 20 April 1809 , Napoleon launched most of his army in an attack to the Southwest . The resulting Battle of Abensberg was a clear , French victory , following which Napoleon ordered all but Davout ' s III Corps and Lefebvre ’ s ( Bavarian ) VII Corps to pursue and destroy what he thought was the remains of the Austrian Army . The French attack , however , had only split the Austrian Army , separating its Left Wing , composed of the V Armee Korps , VI A . K . and II Reserve A . K . , from the balance of the army . Two corps , III A . K . and IV A . K . , were withdrawn by Archduke Charles to the North , forming a nine - mile line from Abbach on the Danube to Eckmühl on the Grosse Laber . More importantly , unbeknownst to Napoleon , the Austrians gained a victory of their own on 20 April 1809 , by surrounding and capturing the French garrison at Ratisbon and its strategic bridge over the Danube . The capture of the bridge at Ratisbon allowed Charles to re - establish contact with his Right Wing , General der Kavallerie Bellegarde ' s I A . K . and FZM Kollowrat ' s II A . K . , hitherto separated from the rest of the Austrian Army by the Danube . Respective Battle Plans . With the seizure of the bridge at Ratisbon , Archduke Charles no longer needed to defend the Landshut bridgehead and instead moved to concentrate his remaining forces so as to envelop and destroy Davout ' s corps . FML Prince Friedrich of Hohenzollern - Hechingen ' s III A . K . ( 15 , 700 men ) and FML Prince Franz Seraph of Rosenberg - Orsini ' s IV A . K . ( 21 , 460 men ) , were ordered to hold the Austrian left , pinning in place Davout ' s corps , while FZM Johann Kollowrat ' s fresh II A . K . ( 28 , 168 men ) and the elite grenadiers and cuirassiers of G . d . K . Prince Johann of Liechtenstein ' s I Reserve A . K . advanced south from Ratisbon and deployed against Davout ' s exposed left flank . Inexplicably , no orders were issued to G . d . K . Count Heinrich von Bellegarde , so his powerful I A . K . ( 27 , 653 men ) remained on the north bank of the Danube and played no role in the subsequent fighting . For his part , Napoleon was intent on enveloping and destroying the Austrian forces retiring Southwest to Landshut and its bridge across the Isar . The II and IV Corps ( App . 57 , 000 men under the overall command of Marshal Masséna ) were directed to cross the Isar upstream from Landshut and block the Austrians from crossing to the South Bank . Meanwhile , under the overall command of Marshal Lannes , Lannes ' Provisional Corps , the VII ( Württemberg ) Corps , a division from VII Corps and two cuirassier divisions ( App . 51 , 000 men ) were to closely pursue and destroy the defeated Austrians . The mop - up of what Napoleon thought was a " curtain of three regiments " was left to Davout , even though more than half of the III Corps ' original units had been detached to create Lannes ' task force . Despite Davout ' s reports to the contrary , Napoleon ordered him to attack the Austrians on his front in the morning , with the proviso that Lefebvre ' s equally depleted corps would support him if he needed help ( A total of approximately 36 , 000 men for both corps ) . 22 April . The leading elements of the Austrian attack ran into Montbrun ' s determined cavalry , who managed to reduce the impetus of the charge thanks to hilly and wooded terrain . Austrian General Rosenberg displayed serious concern when he realized that Davout ' s troops were not moving to account for the ongoing battle , and rightly assumed that more French troops were on the way . These troops had , in fact , arrived and brushed aside Rosenberg ' s flank guard . Napoleon had set the French army into motion around 2 a . m . on the 22nd and had his men march 18 miles north in just a few short hours , meaning reinforcements for Davout would be arriving faster than promised . The vanguard of the assault were the German troops under General Vandamme ; these soldiers stormed the bridge at Eckmühl and even captured the town ' s chateau after ferocious Austrian resistance . At this point , Davout launched his men against the Austrian center at the village of Unterlaichling and the woods to the north . The famous 10th Legere Regiment became involved in vicious fighting around the woods , but eventually was strengthened by Bavarians under Deroy and managed to capture the positions . North of Unterlaichling , Davout ' s troops under Louis Friant and St . Hilaire steadily pushed back the defenders of Oberlaichling and the surrounding woods , overran a redoubt held by Hungarian grenadiers , and prompted Charles to order a general retreat . The struggle now devolved into a series of major cavalry clashes as the Austrians attempted to extricate their army without losing too many prisoners . Perhaps the best cavalry in the Habsburg army , the Vincent Chevaulegers and the Stipsic Hussars , occupied the Bettelberg ridgeline between Eckmühl and the woods above Unterlaiching . These elite units demolished some German light cavalry before being stopped by Bavarian infantry . Napoleon was insistent on the immediate capture of this position and ordered forward two heavy cavalry divisions under St . Sulpice and Nansouty . These horsemen were pummeled by Austrian artillery but came on nonetheless and managed to saber the gunners after having seen off the enemy cavalry . The first phase of the retreat ended , but it was not over yet . The Austrians had found a chokepoint in the road and were instructed to stem the French tide . Three French cuirassier divisions supported by additional German light cavalry attacked and a swirling melee developed . The Austrians fought heroically but were heavily outnumbered and had to retreat . During this part of the conflict , more French cavalry struck in their flank and the remaining Austrian horse fled north to Ratisbon with great celerity . Aftermath . The French had won the battle , but it was not a decisive engagement . Napoleon had hoped that he would be able to catch the Austrian army between Davout and the Danube , but he didn ' t know that Ratisbon had fallen and thus gave the Austrians a means of escape over the river . Nevertheless , the French inflicted 12 , 000 casualties at the cost of just 6 , 000 , and Napoleon ' s speedy arrival witnessed an entire axial realignment of his army ( from a north - south axis to an east - west one ) that permitted the defeat of the Austrians . Subsequent campaigning led to the French recapture of Ratisbon , Austrian eviction from Southern Germany , and the fall of Vienna .