War of The Fourth Coalition - Prussian Campaign

Prussian Campaign

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 maneuvers 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 William 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 the Duke of Auerstedt by Napoleon. On 17 October, Marshal Jean-Baptiste Bernadotte (redeeming himself somewhat for his inexplicable absence from either battle on the 14th,) mauled Eugene Frederick Henry, Duke of Württemberg's previously untouched Reserve corps at the Battle of Halle and chased it across the Elbe River.

Some 160,000 French soldiers fought against Prussia, (increasing in number as the campaign went on, with reinforcements arriving across the Wesel bridgehead from the peripheral theatre surrounding the recently minted Kingdom of Holland), advancing with such speed that Napoleon was able to destroy as an effective military force the entire quarter of a million-strong Prussian army. The Prussians sustained 25,000 casualties (including the deaths of two members of the royal family), lost a further 150,000 prisoners, over 4,000 artillery pieces, and over 100,000 muskets stockpiled in Berlin. Napoleon entered Berlin on 27 October 1806 and visited the tomb of Frederick the Great, there instructing his marshals to remove their hats, saying,

In total, Napoleon and the Grande Armée had taken only 19 days from the commencement of the invasion of Prussia until essentially knocking it out of the war with the capture of Berlin and the destruction of its principal armies at Jena and Auerstadt. Most of the shattered remnants of the Prussian army (and the displaced royal family) escaped to refuge in Eastern Prussia near Königsberg, eventually to link up with the approaching Russians and continue the fight. Meanwhile Saxony was elevated to a kingdom on 11 December 1806 upon allying with France and joining the Confederation of the Rhine, thereby leaving the Allied Coalition.

In Berlin, Napoleon issued a series of decrees which, on 21 November 1806 brought into effect the Continental System. This policy aimed to eliminate the threat of the United Kingdom by closing French-controlled territory to its trade.