Jena-Auerstedt, 1806: Prussia falls in a day

On 14 October 1806, on the same day and on two separate fields, two battles destroyed the army of Prussia. At Jena Napoleon crushed a Prussian wing, while at Auerstedt his marshal Davout, badly outnumbered, beat the main Prussian army. Together they brought down the state built on the legend of Frederick the Great in a single afternoon.²

A war begun too late

Prussia had stayed out of the war that ended at Austerlitz, then declared war in 1806 with an army still living on its old reputation. Napoleon moved first, marching his corps rapidly through the forests of Thuringia to fall on the Prussians before they were ready.³

The road to war ran through a year of humiliations. Napoleon had pushed Prussia into annexing Hanover, which set it against Britain, and then built the Confederation of the Rhine, a French-protected league of western German states, on its doorstep. Anti-French feeling hardened in Berlin, Prussia signed a secret alliance with Russia, and in August King Frederick William III ordered his army to mobilize. In mid-September the Prussians marched into Saxony and brought its elector over to their side.⁴

It was a bad moment to fight. The French were already in Germany, Austria had been knocked out of the war at Austerlitz, and the Russians were still far away behind the Vistula. Britannica's history of the wars lists the Prussian army's weaknesses: little light infantry, poor artillery, cumbersome supply trains, no divisional system, and three separate armies under elderly commanders. Its first and fundamental mistake, the same account argues, was to advance instead of falling back behind the Elbe to wait for the Russians.⁵

Through the Frankenwald

Napoleon struck from the south. On 5 October he ordered the Grande Armée to march northeast in three columns through the wooded hills of the Frankenwald, aiming at the upper Saale to get behind the Prussian left. On 9 October the French brushed aside a Saxon division at Schleiz, and the next day they routed a Prussian detachment at Saalfeld.⁶

Saalfeld cost Prussia a prince. Louis Ferdinand of Prussia, commanding the advance guard, was trying to rally his fleeing troops when his horse was caught in a hedge. A sergeant of the French 10th Hussars, Jean-Baptiste Guindey, ordered him to surrender; the prince refused, slashed at him, and was run through in the fight that followed. The news shook Prussian morale four days before the decisive battles.⁷

Alarmed that they might be cut off from the Elbe, the Prussians fell back to concentrate around Weimar. On 12 October Napoleon wheeled his army west toward the Saale. Prince Hohenlohe's army withdrew toward Jena, the main army under the Duke of Brunswick and the king himself began to retreat north, and Marshal Davout's III Corps stood at Naumburg, astride the road the Prussians would have to take.⁸

Armies and commanders

About 240,000 French, Prussian and Saxon soldiers were in the field on 14 October, according to the Fondation Napoléon. Britannica puts the French at 122,000 against 114,000 Prussians and Saxons. Frederick William III had placed 63,000 men under the Duke of Brunswick near Auerstedt and about 51,000 under Hohenlohe on a 15-mile front between Weimar and Jena, with a further corps under General Rüchel near Weimar.⁹

The Prussians had divided their strength between three armies under elderly commanders. On the French side Napoleon had the corps of Lannes, Augereau, Ney and Soult and Murat's cavalry near Jena, while to the north lay the corps of Davout and Bernadotte. Napoleon was convinced that the whole Prussian army stood in front of him at Jena.¹⁰

Jena: the battle in the fog

On the night of 13 October Lannes's corps climbed the steep Landgrafenberg above Jena, and Napoleon spent the night there laying out his commanders' positions. The attack began at about six in the morning in thick fog. Suchet's division felt its way forward and took the village of Closewitz, and by mid-morning General Tauentzien's Prussian advance guard had been driven off the heights.¹¹

Britannica's figures capture the shape of the day: Napoleon committed only about 54,000 of his 96,000 men at first against Hohenlohe's 38,000. More French troops kept arriving through the late morning, and by about ten o'clock the fighting was intense around the village of Vierzehnheiligen. Marshal Ney attacked between Krippendorf and Isserstadt and was briefly isolated before Augereau's corps came up beside him.¹²

Around one in the afternoon the main French attack went in. The Prussian and Saxon lines broke at Vierzehnheiligen and the retreat turned into a rout. Rüchel's 15,000 men arrived from Weimar too late and counterattacked near the Sperlingsberg at about two o'clock; French guns broke them in less than half an hour. The Saxons fighting at the Schnecke were overwhelmed, many taken prisoner. By three o'clock Napoleon had swept Hohenlohe's men and their reinforcements from the field, and Murat's cavalry was riding the fugitives toward Weimar.¹³

John Rickard of HistoryOfWar.org puts the Prussian losses at Jena alone at about 11,000 killed and wounded and 15,000 prisoners, nearly half of those engaged, against some 5,000 French. That evening Napoleon believed he had beaten the main Prussian army. He soon learned otherwise.¹⁴

Auerstedt: Davout's stand

To the north, at a distance F. Loraine Petre puts at fully thirteen miles as the crow flies, the real Prussian main army had run into Davout. The marshal had 26,000 men; Brunswick had about 63,000. Bernadotte's corps, which should have supported Davout, took almost no part in either battle. Davout's leading division met the Prussian advance near the village of Hassenhausen, and from about nine o'clock the fighting was fierce.¹⁵

Brunswick threw away his advantage in piecemeal attacks, and Davout's divisions held. Then Brunswick himself was shot through the left eye near Hassenhausen. He died of the wound weeks later. The king took command, but the Prussian attacks lost their drive. For six hours Davout's single corps stood firm against a much stronger enemy.¹⁶

When news of the disaster at Jena reached the Prussians, their resistance slackened. Davout brought up his artillery to rake the whole Prussian line and went over to the attack, and by four in the afternoon the Prussian army had disintegrated. The king ordered a retreat toward Weimar and learned only on the march how complete the defeat at Jena had been. Napoleon later made Davout Duke of Auerstedt.¹⁷

Two fields, one day

At Jena, Napoleon attacked what he believed was the main Prussian army and drove it from the field. In truth the larger force lay to the north, where Davout's single corps met it at Auerstedt. Badly outnumbered, Davout held, counterattacked, and won one of the great victories of the era.¹⁸

The two victories cost the French about 12,000 casualties, according to Britannica, against about 24,000 Prussians and Saxons killed and wounded and some 20,000 more taken prisoner. The Fondation Napoléon gives 30,000 to 35,000 dead and wounded on both sides together. Whatever the exact count, the field army of Prussia had ceased to exist in one day.¹⁹

The pursuit

What followed was as decisive as the battles. French cavalry rode the broken Prussians into the ground, and fortress after fortress surrendered with barely a fight. Within weeks Napoleon entered Berlin.²⁰

Britannica calls it the most famous pursuit of the Napoleonic period. It began on 15 October and did not let the Prussians regroup. Bernadotte, making up for his absence on the 14th, beat the Prussian reserve at Halle on 17 October. Davout's corps was given the honor of entering Berlin first. Hohenlohe surrendered to Murat on 28 October, and Blücher's column, cornered near Lübeck, capitulated in the first week of November. Of the whole Prussian army only about 15,000 men under General Lestocq escaped to East Prussia.²¹

Frederick William III fled east to his Russian ally, and the war moved on into Poland and East Prussia, where it went on through the winter at Eylau and ended with the Russian defeat at Friedland and the peace of Tilsit.²² › Battle of Friedland, 1807

What the day decided

Prussia lost its field army, and after further defeats alongside its Russian ally it was forced into a humiliating peace at Tilsit in July 1807. From Berlin, Napoleon proclaimed the Continental System against British trade. The shock also drove Prussia to reform its army from the ground up, changes that would help bring Napoleon down less than a decade later.²³

The treaty signed at Tilsit on 9 July 1807 cut Prussia roughly in half. It gave up all its lands between the Rhine and the Elbe to rulers of Napoleon's choosing, and the Polish provinces it had taken in the partitions became a new Duchy of Warsaw under the king of Saxony. For Poles, the road from Jena led to the first Polish state since the partitions, small and dependent on France as it was.²⁴

The reforms born from defeat

Jena-Auerstedt did more than lose a battle; it shattered the myth of the army Frederick the Great had built. The speed of the collapse convinced a generation of Prussian officers that drill and rigid line tactics were no match for Napoleon's flexible corps. In the years that followed, reformers led by Gerhard von Scharnhorst and August von Gneisenau rebuilt the army from the ground up: they opened the officer corps to talent rather than birth, created a professional general staff, and laid the basis for a trained reserve. The humiliation of 1806 was the seed of the Prussian army that would help bring Napoleon down at Leipzig in 1813 and Waterloo in 1815.²⁵ › The Battle of Leipzig, 1813

Visiting the battlefield today

Both fields can still be walked. Above Jena, the Museum 1806 at Cospeda on the Landgrafenberg plateau tells the story of the battle with maps, dioramas and eyewitness accounts, and the Napoleonstein nearby marks the hill where the emperor spent the night before the battle; the original stone was lost and a replacement was set up in 1991. Guided tours cover the Windknollen and the Landgrafenberg, and the battle is re-enacted around its anniversary.²⁶

Monuments are scattered across the Jena field, around Vierzehnheiligen, the Krippendorf windmill and the Sperlingsberg. To the north, a memorial site at Hassenhausen recalls Davout's stand, a monument to the Duke of Brunswick stands on the road between Taugwitz and Hassenhausen, and Auerstedt Castle houses a museum.²⁷ › The Greatest Napoleonic Battles