page_title: War of the Fourth Coalition
section_title: Prussian campaign
hierarchical_section_title: War of the Fourth Coalition / Prussian campaign
caption_attribution_description: English: Siege of Danzig 1807
context_page_description: The Fourth Coalition fought against Napoleon's French Empire and were defeated in a war spanning 1806–1807. The main coalition partners were Prussia and Russia with Saxony, Sweden, and Great Britain also contributing. Excluding Prussia, some members of the coalition had previously been fighting France as part of the Third Coalition, and there was no intervening period of general peace. On 9 October 1806, Prussia joined a renewed coalition, fearing the rise in French power after the defeat of Austria and establishment of the French-sponsored Confederation of the Rhine. Prussia and Russia mobilized for a fresh campaign with Prussia massing troops in Saxony.
  Napoleon decisively defeated the Prussians in an expeditious campaign that culminated at the Battle of Jena–Auerstedt on 14 October 1806. French forces under Napoleon occupied Prussia, pursued the remnants of the shattered Prussian Army, and captured Berlin. They then advanced all the way to East Prussia, Poland and the Russian frontier, where they fought an inconclusive battle against the Russians at the Battle of Eylau on 7–8 February 1807.
context_section_description: Influenced by his wife Queen Louise and the war party in Berlin, in August 1806 the Prussian king Friedrich Wilhelm III made the decision to go to war independently of any other great power, save the distant Russia.  Another course of action might have involved openly declaring war the previous year and joining Austria and Russia in the Third Coalition. In fact, the Tsar had visited the Prussian king and queen at the tomb of Frederick the Great in Potsdam that very autumn, and the monarchs secretly swore to make common cause against Napoleon. Had Prussian forces been engaged against the French in 1805, this might have contained Napoleon and prevented the eventual Allied disaster at Austerlitz. In any event, Prussia vacillated in the face of the swift French invasion of Austria and then hastily professed neutrality once the Third Coalition was crushed. When Prussia did eventually declare war against France in 1806, its main ally the Russians still remained far away remobilising. The electorate of Saxony would be Prussia's sole German ally.
  Napoleon could scarcely believe Prussia would be so foolish to take him on in a straight fight with hardly any allies at hand on its side, especially since most of his Grande Armée was still in the heart of Germany close to the Prussian border. He drummed up support from his soldiers by declaring that Prussia's bellicose actions had delayed their phased withdrawal back home to France to enjoy praise for the previous year's victories. Once hostilities seemed inevitable in September 1806, Napoleon unleashed all French forces east of the Rhine, deploying the corps of the Grande Armée along the frontier of southern Saxony. In a preemptive strike to catch the Prussians unaware, the Emperor had the Grande Armée march as a massive bataillon carré (battalion square) in three parallel columns through the Franconian Forest in southern Thuringia. Each corps would be in mutual supporting distance of each other, both within the column and laterally to the other columns (once through the difficult passage of the forest), thus allowing the Grand Armée to meet the enemy at any contingency. This strategy was adopted due to Napoleon's lack of intelligence regarding the Prussian main army's whereabouts and uncertainty over his enemy's puzzling manoeuvres in their march to face him. The reason for this stemmed mainly from the mutual mistrust within the Prussian high command that had resulted in division among the Prussian commanders over which plan of action for the war would be adopted. Despite the deficiency in pinpointing the main Prussian army's exact position, Napoleon correctly surmised their probable concentration in the vicinity of Erfurt and formulated a general plan of a thrust down the Saale valley, enveloping the left flank of where he believed the Prussians were located and thus cutting off their communications and line of retreat to Berlin.
  In the first clash on 9 October 1806, a Prussian division was brushed aside in the Battle of Schleiz. The following day, Marshal Lannes crushed a Prussian division at Saalfeld, where the popular Prince Louis Ferdinand was killed. At the double Battle of Jena-Auerstedt on 14 October, Napoleon smashed a Prussian army led by Frederick Louis, Prince of Hohenlohe-Ingelfingen and Ernst von Rüchel at Jena, while his Marshal Louis-Nicolas Davout routed Charles William Ferdinand, Duke of Brunswick's main army at Auerstedt. At Jena, Napoleon fought only a contingent of the Prussian army. At Auerstedt a single French corps defeated the bulk of the Prussian army, despite being heavily outnumbered. Victory at Auerstedt was all but secured once the Duke of Brunswick (as well as fellow commander Friedrich Wilhelm Carl von Schmettau) were mortally wounded, and the Prussian command devolved to the less able King. Matters were worsened once the vanquished remnants of the Prussian army from Jena stumbled onto the clash at Auerstedt, further plunging the Prussians' morale and triggering their precipitous retreat. For this conspicuous victory, Marshal Davout was later created 
caption: The Siege of Danzig, 1807
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