The stunning speed with which Napoleon overthrew the much-vaunted Prussian army in the fall of 1806 was dramatic, even by the standards this great captain set. Following on from his decisive defeat of the Austro-Russian army at Austerlitz in December 1805, Napoleon now established himself as master of central Europe with the Jena- Auerstädt campaign, ending attempts by Russia to play a significant role in European affairs for several years.
Since the Treaty of Basle of 1795, Prussia had maintained a policy of neutrality with France, but the incessant expansion of the Napoleonic Empire caused friction in government circles in Berlin and led to increasing calls for war with France. The war party in Prussia grew in influence.
When war broke out between Britain and France in 1803, General Adolphe Mortier occupied Hanover and disbanded its army. Prussia, supposedly the defender of north Germany, did not oppose this act. Effectively, the Treaty of Basle had ceased to have force. King Frederick William III did everything he could to avoid giving Napoleon cause for a confrontation and ignored suggestions that he should mobilize a corps of observation. When the War of the Third Coalition of Austria, Russia, Britain, and Sweden began in 1805, Napoleon sought to ensure Prussia’s neutrality by offering it Hanover. Frederick William was tempted but rejected this offer, as Napoleon made recognition of his conquests in Italy a prerequisite. Russia also put pressure on Frederick William, demanding the right of passage through Prussian territory for its forces. Caught in the middle, part of the Prussian army was mobilized that September.
Hardly had this mobilization begun when a French corps under Marshal Jean-Baptiste-Jules Bernadotte violated Prussian neutrality. This corps marched from Hanover southward through the Prussian enclave of Ansbach on 3 October, looting and pillaging as it went. This caused considerable outrage in Prussia and led to calls for war. The Russians were finally allowed passage through Prussian territory. Around 180,000 Prussian troops were placed on a war footing.
Napoleon needed to act quickly, and act quickly he did. His rapid maneuvers caused an Austrian force in southwest Germany under Feldmarschalleutnant Karl Mack Freiherr von Leiberich to capitulate at Ulm. While Prussia was trying to negotiate an armed peace, the French moved on Vienna. By the Treaty of Potsdam, concluded on 3 November, the Prussians agreed to enter the war with an army of 180,000 men, including contingents from Saxony and Hesse, should Napoleon refuse to make peace within four weeks of the departure from Berlin of the Prussian envoy Christian Graf von Haugwitz. Napoleon kept him at arm’s length until after his victory at Austerlitz on 2 December. The strategic situation now having been so fundamentally changed, Haugwitz agreed to an exchange of territory with Napoleon, ceding the Prussian possessions of Ansbach, Cleves (Kleve), and Neuchatel (a Prussian enclave in Switzerland) in return for Hanover. But peace had come at a price. The acquisition of Hanover led Prussia into a dispute with Britain, its only potential ally in Europe now. Prussia was now isolated.
Seeing his chance, Napoleon started to goad Prussia into war. Joachim Murat, a French marshal and the Grand Duke of Berg, seized Prussian territory at Verden and Essen, in western Germany. French troops massed in Berg, threatening Prussia. Napoleon had suggested that Prussia should form a North German Confederation, but he then prevented it from carrying this out. Having induced Frederick William to accept Hanover, Napoleon then commenced peace negotiations with Britain, offering to return this territory. He did so without Prussia’s knowledge, but the Prussian ambassador in Paris discovered it. This was the final provocation and the immediate cause for war.
Despite the gravity of the situation and the obvious, growing threat from France, Prussia entered this war ill prepared, and it lacked unity both in the government and in the higher command of the army. Frederick William did not have the strength of character or the authoritative demeanor necessary to impose his will on the arguing generals and politicians. The constant bickering hampered all operations. Nevertheless, Tsar Alexander I of Russia, irritated by the failure of his negotiations with Napoleon, promised to help, but his forces were far away. Britain too offered aid but moved slowly. Sweden declared its support but could do little. All that joined Prussia immediately was a contingent from Hesse and the reluctant Saxon army.
On 9 August 1806 the Prussian forces were ordered to mobilize. They entered this conflict with great expectations. Although the army had not been to war for ten years, its leaders had observed the development of warfare in the ensuing campaigns and had introduced a number of reforms. However, these attempts at modernization were underfunded and achieved less than was necessary. Napoleon’s army had been fully trained at the camp at Boulogne, and its veteran cadres were flushed with the great victories of 1805. Napoleon’s well-honed forces faced the army Europe respected above all others. The stage was set for the forthcoming War of the Fourth Coalition.
Strategically and politically, Prussia’s position was not straightforward. France was one of Europe’s most populous countries at this time, with a population of nearly 30 million. Prussia had the resources of only 8.7 million people, 2.5 million of whom were Poles, many of whom had only become Prussian subjects through the recent partitions of their country. Russia’s support was essential, but Russia was considered an unreliable ally. There were rumors it was discussing peace with Napoleon, but these rumors were quashed on 3 September when a report arrived in Paris that Alexander had rejected Napoleon’s overtures. As a result, Napoleon now refused to remove his troops from southern Germany and began his preparations for war.
The Prussians feared Napoleon would strike first. France’s occupation of the left bank of the Rhine left General Gebhard von Blücher’s men in Westphalia out on a limb. The fate of Mack’s Austrians the previous year must have been fresh in everybody’s minds. Plans were made to withdraw Blücher’s men over the river Elbe, but this would have left the Hessians in an exposed position and caused the Saxons consternation. Blücher also considered that his Westphalians would be reluctant to leave their home area, and he feared many would desert. Instead, the Prussians decided to concentrate to the fore, furthest away from the Russians. This would exacerbate the general strategic weakness of their position.
The Prussians raised a field army of seven corps of varying strengths: the Westphalian, the Hanoverian, the Magdeburg, the 1st Reserve, the Silesian, the West Prussian, and the Pomeranian. The fortresses of Magdeburg, Hamlin, and Nienburg were placed in a state of defense. To increase the mobility of the army, much of the heavier artillery pieces were left behind and the baggage train was reduced to a minimum. However, these measures were taken too far, for large parts of the army ran out of ammunition. The East Prussians were not mobilized, as they were needed to keep an eye on the Russians.
After some deliberations, the main part of the Prussian forces, around 65,000 men, were placed under the command of Charles, Duke of Brunswick, while Friedrich Ludwig Fürst Hohenlohe-Ingelfingen (known as Hohenlohe) was given command of a Prusso-Saxon corps of around 45,000 men. A corps of 34,000 men was left to cover Westphalia and Hesse, and 18,000 West Prussians were left in reserve. Brunswick and Hohenlohe were deployed facing Napoleon’s forces concentrating in southern Germany.
On 26 September 1806 Prussia sent an ultimatum demanding the immediate withdrawal of the French armies across the Rhine and Napoleon’s assent to the formation of the promised North German Confederation under Prussian leadership. Napoleon did not bother to respond, so on 8 October Prussia declared war. Napoleon was better prepared for this eventuality, having kept the Grande Armée in Germany for that very purpose. He concentrated his 180,000 men on the river Main, determined to strike at Berlin before help could arrive from Russia.
Napoleon was now assembling his IV (under Marshal Nicolas Soult), VI (under Marshal Michel Ney), and VII (under Marshal Pierre-François-Charles Augereau) Corps in Franconia. On 3 October Marshal Louis Davout’s III Corps arrived in Bamberg and Marshal François Lefebvre’s V Corps was moving to join them. The Prussians moved into Saxony to meet them. Napoleon’s plan was simply to locate and destroy the Prussians before any assistance from the Russians could arrive. An advance from southern Germany on Berlin would isolate the Prussians in the west, forcing them to withdraw.
The Prussians, only 145,000 strong, decided to seek victory alone rather than fall back toward the east and await the arrival of the tsar’s forces. The difference in numbers was not in itself decisive, but there is only one thing worse than dividing one’s army into two before the enemy, and that is dividing it into three, which is precisely what the Prussians did. Frederick William had not been able to get Brunswick to collaborate with Hohenlohe, so each was allowed to take the measures he considered appropriate. A third force of 15,000 men under General Ernst Friedrich Wilhelm von Rüchel was also formed. They faced 180,000 of Napoleon’s veterans under a unified command. The resulting confusion diminished the chances of a successful outcome.
Napoleon now moved into Saxony marching in three columns. Soult (IV Corps) led the right column, about 40,000 men strong, with Ney (VI Corps) and the Bavarian contingent following him. It moved via Hof on Plauen. Bernadotte (I Corps) led the center column, about 70,000 men, with Davout (III Corps), much of the Reserve Cavalry, and the Imperial Guard following him. They moved from Kronach in the direction of Schleiz. The V Corps, now under Marshal Jean Lannes, led the left column, about 50,000 men, followed by Augereau (VII Corps). They moved toward Saalfeld and crossed the frontier on 8 October.
Fortunately for Napoleon, the Prussians had neglected to block the passages through the Thüringian Forest. The Grande Armée’s three columns formed into a bataillon carré (battalion square), which would allow it to counter any offensive actions from the Prussians. The column attacked would simply fight a delaying action, falling back if necessary, allowing the remaining columns to swing into action against the Prussian flank. That day ended with Lannes’s column moving toward Saalfeld and Soult’s moving toward Hof. Matters were going well for Napoleon. The unity of command and the greater experience of recent warfare gave the French a considerable advantage.
The lack of a single command and of a clear objective hindered Prussian countermoves. The first sign of what was to come took place at Saalfeld on 10 October. Here, Lannes overwhelmed and defeated an exposed Prusso-Saxon force of around 8,000 men under the youthful and impetuous Prince Louis Ferdinand of Prussia, who was killed in action. This body of men was the vanguard of Hohenlohe’s corps. It had been outnumbered 2 to 1 in this combat, so the result was to be expected. However, the death of the popular prince at the hands of a French hussar caused consternation in both the army and the nation. The frictions between the Prussians and the Saxons increased. The rot began to set in.
Expecting the Prussians to fall back on Gera to cover Leipzig, Napoleon marched north in the hope of catching the Prussian corps individually. His cavalry patrols located the main Prussian force further to the north or west, not to the northeast. No Prussians were sighted in Gera or on the river Elster. Napoleon concluded that the Prussians were to the west and would offer battle around Erfurt, so he ordered his columns to wheel to the left.
Brunswick declined to hold the line of the river Saale. Hohenlohe fell back on Jena, while Brunswick advanced on Weimar. Bernadotte wheeled toward the center column, while Davout passed through Naumburg. By taking this crossing at the river Unstrut, the French had cut off the Prussians’ intended line of retreat and their communication with Berlin. Their council of war now decided to fall back on Leipzig via Auerstädt, the Kösen Pass, Freyburg, and Merseburg. Hohenlohe was ordered to protect the flank of the main body, occupying the village of Kapellendorf, halfway between Weimar and Jena.
Not expecting to face the Prussians in battle for a few days yet, Napoleon reacted quickly to news of sightings of their actual positions and movements. Believing the main body of the Prussians was on the far side of Jena, he decided to strike, calling in the support of parts of the right column to join the left and center.
The battles of Jena and Auerstädt were confused affairs. At Auerstädt, Brunswick, with 50,000 men, bumped into Davout’s force of 27,000 men blocking his line of retreat. Davout’s successful defense of Hassenhausen is legendary. He repelled Brunswick, who was mortally wounded, leaving his men leaderless.
Napoleon met what he considered the main Prussian force at Jena. He started the affair with around 55,000 men against Hohenlohe’s 40,000 Prusso-Saxon corps. Another 40,000 men had joined Napoleon by noon, and weight of numbers told. Rüchel’s force of 15,000 men arrived too late to play much of a part other than to get caught up in the confusion of retreat. Although driven back in disorder, the Prussians had not disgraced themselves, but Napoleon pursued with vigor, turning the retreat into a rout. Napoleon considered that his victory at Jena had expunged the stain of the French defeat at Rossbach during the Seven Years’ War (1756-1763).