Battle of Ulm - Background

Background

In 1805, the United Kingdom, the Austrian Empire, Sweden, and the Russian Empire formed the Third Coalition to overthrow the French Empire. When Bavaria sided with Napoleon, the Austrians, 72,000 strong under Mack, prematurely invaded while the Russians were still marching through Poland. The Austrians expected the main battles of the war to take place in northern Italy, not Germany, and intended only to protect the Alps from French forces.

A popular but apocryphal legend has it that the Austrians used the Gregorian calendar, the Russians were still using the Julian calendar. This meant that their dates did not correspond, and the Austrians were brought into conflict with the French before the Russians could come into line. This simple but implausible explanation for the Russian army being far behind the Austrian is dismissed by scholar Frederick Kagan as "a bizarre myth".

Napoleon had 177,000 troops of the Grande Armée at Boulogne, ready to invade England. They marched south on August 27 and by September 24 were ready to cross the Rhine from Mannheim to Strasbourg. After crossing the Rhine, the greater part of the French army made a gigantic right wheel so that its corps reached the Danube simultaneously, facing south. On October 7, Mack learned that Napoleon planned to cross the Danube and march around his right flank so as to cut him off from the Russians who were marching via Vienna. He accordingly changed front, placing his left at Ulm and his right at Rain, but the French went on and crossed the Danube at Neuburg, Donauwörth, and Ingolstadt. Unable to stop the French avalanche, Michael von Kienmayer's Austrian corps abandoned its positions along the river and fled to Munich.

On 8 October 1805, Franz Auffenberg's division was cut to pieces by Joachim Murat's Cavalry Corps and Jean Lannes' V Corps at the Battle of Wertingen. The following day, Mack attempted to cross the Danube and move north. He was defeated in the Battle of Günzburg by Jean-Pierre Firmin Malher's division of Michel Ney's VI Corps which was still operating on the north bank. During the action, the French seized a bridgehead on the south bank. After first withdrawing to Ulm, Mack tried to break out to the north. His army was blocked by Pierre Dupont de l'Etang's VI Corps division and some cavalry in the Battle of Haslach-Jungingen on 11 October.

By the 11th, Napoleon's corps were spread out in a wide net to snare Mack's army. Nicolas Soult's IV Corps reached Landsberg am Lech and turned east to cut off Mack from the Tyrol. Jean-Baptiste Bernadotte's I Corps and Louis Nicolas Davout's III Corps converged on Munich. Auguste Marmont's II Corps was at Augsburg. Murat, Ney, Lannes, and the Imperial Guard began closing in on Ulm. Mack ordered the corps of Franz von Werneck to march northeast, while Johann Sigismund Riesch covered its right flank at Elchingen. The Austrian commander sent Franz Jellacic's corps south toward the Tyrol and held the remainder of his army at Ulm.