The Battle of Günzburg on 9 October 1805 saw General of Division Jean-Pierre Firmin Malher's French division attempt to seize a crossing over the Danube River at Günzburg in the face of a Habsburg Austrian army led by Feldmarschall-Leutnant Karl Mack von Lieberich. Malher's division managed to capture a bridge and hold it against Austrian counterattacks. The battle occurred during the War of the Third Coalition, part of the larger Napoleonic Wars.
After Mack's Austrian army invaded Bavaria, it found itself the target of a powerful offensive by the army of Emperor Napoleon I of France. When Napoleon's corps threatened to envelop Mack's army, the Austrian general unwisely held his ground near the city of Ulm. As the French armies blocked the Austrian retreat routes to the east, Mack attempted to move his army to the south bank of the Danube. After receiving orders to seize the Danube bridges, Marshal Michel Ney sent Malher to capture the crossing at Günzburg. Malher's main attack on two bridges failed in the face of a vigorous Austrian defense. However, a late-arriving French unit captured the eastern bridge that had just been rebuilt by the Austrians and was able to hold on to it until evening. Discouraged by the encounter, Mack ordered his soldiers to march back to Ulm which is 22 kilometers west-southwest of Günzburg.
Background
War plans
Austria, defeated by France in the War of the Second Coalition and forced to accept a French client state in Italy, planned to take revenge. In November 1804, Austria made a secret alliance with the Russian Empire whereby Austria's 235,000 soldiers would be supported by 115,000 Russian troops and financial backing from Great Britain. The head of the Austrian army, Feldmarschall Archduke Charles, Duke of Teschen believed his soldiers were not ready for war, but the pro-war faction at the court of Emperor Francis I of Austria outmaneuvered him.
Feldmarschall-Leutnant Karl Mack von Lieberich, who had the full confidence of the emperor, became largely responsible for developing Austria's war plan. Mack's strategy called for 120,000 troops in Italy commanded by Charles, 25,000 in the County of Tyrol under Archduke John of Austria, 70,000 in Bavaria under Feldmarschall-Leutnant Archduke Ferdinand Karl Joseph of Austria-Este, and 20,000 in reserve. Mack would accompany Ferdinand's force, which would be joined by a Russian army and attack across the Rhine River into France. Charles would sweep across Italy and invade southern France. It was hoped that the Kingdom of Prussia could be induced to join the coalition. Mack convinced Emperor Francis I that he should invade Bavaria first, while Charles marked time in Italy. The general believed that by the time Napoleon intervened in Bavaria, the Russian army would have arrived to help the Austrians. This erroneous assumption caused Mack and the war hawks to fall into "a comedy of errors". Foreseeing trouble with Mack's plan, Charles talked the emperor into transferring 30,000 soldiers from Italy to Germany, but these troops would arrive too late to remedy the situation.
Napoleon's Grande Armée numbered 219,000 soldiers and consisted of seven corps, the Reserve Cavalry, and the Imperial Guard. Marshal Jean-Baptiste Bessières led the 7,000-strong Imperial Guard; Marshal Jean-Baptiste Bernadotte commanded the 17,000-man I Corps; General of Division Auguste Marmont directed the 20,000 troops of the II Corps; Marshal Louis Davout controlled 26,000 soldiers of the III Corps; Marshal Soult led the 40,000-strong IV Corps; Marshal Jean Lannes had 18,000 men in the V Corps; Marshal Michel Ney commanded the 24,000 soldiers of the VI Corps; Marshal Pierre Augereau directed the 14,000-man VII Corps. Marshal Joachim Murat led the Cavalry Reserve with 22,000 troopers in seven divisions, while the Artillery Reserve had 5,000 gunners.
In the summer of 1805, the Grande Armée lay in its camps on the English Channel. Napoleon planned for the Grande Armée to march to the Rhine, then execute a vast right wheel from the Rhine to the Danube, picking up his 25,000 Bavarian allies on the way. Meanwhile, Marshal André Masséna with 50,000 troops would hold Archduke Charles in northern Italy, assisted by 20,000 reinforcements from central Italy led by General of Division Laurent Gouvion Saint-Cyr. Marshal Guillaume Marie Anne Brune would remain on the northern coast of France with 30,000 soldiers. Napoleon issued his marching orders on 26 August.