In 1805 during the War of the Third Coalition, Emperor Napoleon I decisively defeated the Austrians and Russians at the Battles of Ulm and Austerlitz resulting in the Treaty of Pressburg, which ended Austria’s participation in the war. Without Austrian protection, the Kingdom of Naples was vulnerable and a combined French, Swiss, Italian, and Polish Army of Italy under French Marshal Andre Massena invaded. The Anglo-Russian forces in Italy abandoned the Kingdom of Naples and the Neapolitan Army was crushed at the Battle of Campo Tenese. Bonapartist rule replaced Bourbon on the Italian peninsula until the end of the Napoleonic Wars.

With the end of the War of the Third Coalition, Napoleon turned his attention to creating a German buffer state between France and his traditional enemies, Austria, Prussia, and Russia. Napoleon created the Confederation of the Rhine of German states nominally part of the Holy Roman Empire. The Confederation states withdrew from the Holy Roman Empire and the French Empire formally became known as the “Protector of the Confederation of the Rhine.” Napoleon elevated the two largest, Bavaria and Wurttemberg, to vassal kingdoms within the French Empire and removed them as Electors of the Holy Roman Empire. Napoleon forced Austria, defeated and dejected, to dissolve the Holy Roman Empire, which had stood for a thousand years since its creation by Charlemagne in 800. The creation of the Confederation and the dissolution of the HRE were slaps to the face of the proud Prussians.

Napoleon overran Austria and defeated Russia so quickly that Prussia stayed neutral in the War of the Third Coalition. In recompense for their loss of influence with the dissolution of the HRE and loss of some territory to the Confederation, Napoleon gave the lands of former British ally Hannover to Prussia. In the summer of 1806, Napoleon was caught negotiating the return of Hannover to Great Britain without including Prussia in the negotiations. It was the final insult for the Prussian war faction, led by Queen Louise, and they convinced Kaiser Frederick Wilhelm III to mobilize the army. Not wanting to wait, the Duke of Brunswick convinced the king to attack the French cantonment areas before the French could invade, supported only by the army of the small Kingdom of Saxony. After the Prussian Army mobilized it moved into Saxony and the king issued an ultimatum to Napoleon to withdraw all French troops from the German states.

Napoleon’s Grande Armee was garrisoned in the Confederation of the Rhine. Napoleon refused the ultimatum, and the Prussians invaded. The armies of Prussia’s ally Russia were still far to the east, and unable to come to Prussia’s aid. Napoleon ordered his marshals to advance their corps into Saxony and Prussia immediately. The rapidity with which the French troops assembled from their garrisons and moved across the frontier into Saxony astonished the Prussians, who planned to fight the French in Bavaria and Württemberg, not Saxony or Prussia.

Napoleon’s corps were standardized, self-sufficient, combined arms formations of about 25,000 men consisting of infantry divisions, and cavalry and artillery brigades, with supporting specialists such as engineers, pontoon bridges, and supply trains, all under a trusted subordinate capable of independent command. These commanders were Napoleon’s chosen ones: the Marshals of France, and they were promoted strictly on merit and military efficacy. Generals could be political appointees or promoted because of birth, such as Napoleon’s brother Jerome, but never a marshal. The 26 men chosen over the years by Napoleon to be Marshals of France came from all walks of life, and were a collection of talent and ability rarely seen in history. Only the Diadochi, the Apostles, the Genghis Khan’s generals, the viziers of Suleiman, the Sun King’s advisors, and the Founding Fathers occupy the same historical pedestal. Napoleon trusted his marshals implicitly to carry out his mission orders and did not micromanage them with directives. With the self-sufficiency and inherent initiative of the corps system, and without the burden of a supply tail due to the French Army’s liberal use of foraging, the Marshals and their corps maneuvered much quicker and with more agility than France’s enemies.

Prussia, like the Russians and Austrians, still maintained the army-level unit, an unwieldy formation of about 100,000 men, as the lowest level of synchronization and integration between combined arms. The Prussian Army of 1806 was nearly the same army created by Frederick the Great sixty years before and they had been riding on that reputation ever since. As Carl von Clausewitz pointed out, “Behind the fine façade, all was mildewed.” King Frederick Wilhelm III himself commanded though he had the Duke of Brunswick make all of the tactical and operational decisions. The size of all of the King’s subordinate commands were based on their commander’s rank and noble title, with the cavalry’s disposition and composition based solely on its commander’s noble title. Through some misguided half-reforms, the Prussians created divisions but they had too much cavalry and artillery since their composition was based on the prestige of the commander. This over compensation i.e. more is better, made the divisions difficult to move, and diluted the striking power of the cavalry and artillery, thus the need for army level coordination. With no standardization in units above brigade, these commands were unwieldy and their movements ponderous and use of the road network inefficient. The Prussian staffs were overly bureaucratic, and riven by poisonous rivalries common in staffs accustomed only to garrison operations. There were two generals staffs, one established for decades that ran administration and the recently approved operational staff. Neither had priority over the other and saw each other as rivals. Both of the staffs worked at cross purposes. Senior commanders, most nearly twice the age of their French counterparts, spent much time untangling the mess, usually by committee since Brunswick wanted to stay above the fray. The result was a Prussian army more concerned about internal politics than fighting the French. In September 1806, the combined Prussian and Saxon armies advanced on the Thuringian Forest to invade the Confederation of the Rhine, but by then the French were prepared. The Prussian dithering cost them an entire month, which was more time than Napoleon needed to mobilize the Grande Armee.

Simultaneously with the Prussian invasion, Napoleon’s Grande Armee advanced into Saxony threatening Leipzig, and from there, Magdeburg, which would cut off Berlin. On three parallel routes, each of its seven corps moved north within a day’s march of each other over routes carefully reconnoitered by scouts. The seven corps advanced in a rough arrowhead with three corps on the middle road, two each on the east and west roads, and Napoleon and the Imperial Guard in the middle. Napoleon famously called it “a gigantic battalion box”. The Prussian Army was not capable of this feat of disciplined cohesive movement born of precise and efficient staff work. Several days into their march south, the Prussian Army was forced to concentrate on Erfurt for the final push into Bavaria. There, Brunswick learned of Napoleon’s nearby invasion of Saxony. Napoleon was pushing north to the east of the Prussians as the Prussians, to the west of the French, were passing the French while pushing south.

Brunswick hoped to threaten Napoleon’s flank and defeat him piecemeal as he passed, but the speed and agility of Napoleon’s corps left him out of position. The Grande Armee moved too quickly and any opportunity to attack passed. So Brunswick ponderously turned his army back north to find somewhere to defeat Napoleon, he had no choice but to fight. Through just good staff work, the French Army severed communication between Brunswick and his capitals, and more importantly, from any assistance from the Russians.

The first battles with Prussians at Auma, Schleitz and Saalfeld in early October 1806 were the first indications that the Prussians were to the west across the Saale River. The aggressive assault by the Prussian vanguard at Saalfeld by the unusually competent Prince Louis Ferdinand convinced Napoleon that the main Prussian Army was west of the Saale. On 13 October, Lannes’ V Corps made contact with a large Prussian force at Jena, which they forced back across the river. Napoleon, assuming Lannes found the Prussian main body, concentrated the Grande Armee. Napoleon’s seven corps quickly shifted toward the river crossings to seize and cross before the Prussians could defend them. Napoleon wanted to bring the Prussian Army to battle, but not force the river. If the Grande Armee moved quickly enough, it could catch the Prussians by surprise on the Landgrafenburg, the plateau west of Jena, which was where they had to camped. Napoleon, Soult, Augereau, and Ney, led by Lannes’ V corps crossed the Saale at Jena, while Davout supported by Bernadotte were to cross further downstream and fall on the Prussians from the north.

Jena was a university town and home of the German romanticists, and the home of the nascent unified German culture. The town was generally pro-Napoleon and saw La Grande Armee as the vanguard of the modernizing French Revolution come to rescue Germany from feudalism. The French sacked the town and accidentally burned it to the ground while foraging.

The Prussian Army had to be found. But before that could even happen, Napoleon’s corps needed to occupy the Landgrafenburg, the high plateau west of Jena to form a proper battle line. To get there, a perpendicular narrow ridge needed to be traversed by the French and this formed a natural choke point. On the morning of 14 October, 1806, Lannes already had a toehold on this ridge, which his men seized the night before. Neither this ridge nor Jena and its vital bridge over the Saale were defended by the nearby Prussian force under the Prince of Hohenlohe, nor were the French attacked while in this vulnerable position. These failures were even more unconscionable since the Prussians knew the French were in Jena the night before. Unhindered, Lannes’ scaled the ridge and formed a battle line on the Landgrafenburg.

The fog on the morning of 14 October 1806 was all pervasive. Lannes’ light infantry and cavalry scouted further west and found Prussian troops of von Tauentzien’s reinforced flank guard division. Lannes immediately attacked and destroyed von Tauentzien’s divison which fled west, while a detachement under Holtzendorff retreated north. Lannes succeeded in making room for the four more corps and the Imperial Guard coming up behind him.

The French attack came as a surprise to Hohenlohe. One of his subordinates, Gen-Lt Gravert marched his division to the sound of the guns but was halted by Hohenlohe and chastised. Hohenlohe, from his headquarters in the Kappelburg Castle, was not prepared to fight a major engagement yet and his staff had not prepared the necessary orders. Gravert convinced Hohenlohe that he was in a battle whether he liked it or not. The Prussians deployed in a battle line opposite the town of Vierzehnheilegen which they thought (correctly) was between Napoleon and themselves.

After the destruction of the flank Prussian division, Napoleon also halted his attack. He knew the rest of the Prussian Army was to the west of him but not where – the fog was too thick. As Augereau’s VII Corps arrived to the left of Lannes and Soult’s IV Corps to the right, Napoleon ordered forward his light infantry and cavalry to find the Prussians while the rest of the army waited in the fog. Napoleon’s light infantry occupied the town of Verzehnheilegen and watched Hohenlohe’s columns ponderously turn into a line facing the town.

(I honestly can’t adequately convey the complexity of this Prussian maneuver. The training time to execute this parade ground drill on command must have been massive. It’s a combination of column right by file from the left into a right facing line. Whereas the French did a simple “right flank, march”, the Prussian method maintained that the first file (on the left) must always be the file facing the enemy, thus the complicated drill when the enemy was on the right.)

Hohenlohe’s orders from Brunswick were to not become decisively engaged as his mission was to screen the flank of the main army 30 km away. Brunswick headed north on a parallel route to Napoleon to find another position to fight the French. When Napoleon agilely crossed the Saale at Jena, he thought that the main army was to the west or, optimistically, the Prussian left flank guard. The destruction of Tauentzien’s division and Holtzendorff’s cavalry earlier in the morning lent credence to this theory. But Hohenlohe wasn’t the vanguard or even the left flank guard, but the right flank guard, with the main Prussian army 30 kms away marching north, not south. Moreover, they were marching on roads they just passed over a few days previously going in the opposite direction. The closest Prussian units to Hohenlohe wasn’t the main body but the Prussian reserve bringing up the rear of the main army. Hohenlohe wasn’t going to attack the French, but he wasn’t going to run away either, thanks to Gravert. Unfortunately for Hohenlohe, the Prussian main body was marching further away every minute.

The first indications that the French were nearby since the firing stopped were Tauentzien’s routed formations streaming through the line. The broken men did little for the morale of Hohenlohe’s battle line but iron Prussian discipline held the men in formation. Hohenlohe advanced the formation forward until they came within sight of Versehnheilegen. Astonishingly, the French light infantry, or voltigeurs, spread out in the meadows just outside of the town. Unlike the Prussian line infantry, or French line infantry in close formation, the French light infantry used all of the cover and concealment that the town and gently rolling fields offered. Every copse of trees, every fold of ground, every orchard tree, every hedge, wall, building, and window hid voltigeurs, who weren’t going to stand and receive the disciplined Prussian volleys.

The Prussians had no effective counter as the concept of light infantry was practically alien to them. They understood the need for open order skirmishers but unlike the French, the Prussians light troops were trained in highly ritualized and rigid open order formations, which were almost never used. Open order troops were seen as diluting the decisive firepower of the line. The initiative and trust needed by a light infantryman was an anathema to the harsh and rigid discipline required by the line. To Prussian officers in 1806, placing that much trust in infantry in open formation was tantamount to obliging them the opportunity to desert. The Prussians did form a “jaeger” regiment armed with rifles who were trained to fight in open order, but they were considered an elite, and recruited from the upper and professional classes. Their loyalty was never suspect, but there was only a single regiment of them in the entire Prussian Army of 1806. In the Grande Armee, there was one specially trained voltigeur company per regiment, but all French infantry were expected to competently perform in any formation, whether column, line, line, or square, or open or closed. Revolutionary fervor, meritocratic officers, and the daily realities of foraging ensured that French infantry operating in an open formation would not desert, at least in 1806. Napoleon said later that La Grande Armee of 1806 was his finest.

The French voltigeurs took a terrible toll on the Prussian line, particularly the officers. Hohenlohe formed a vanguard to clear the menace, and hearing them being shot to pieces, pushed artillery forward to sweep the fields and town with canister. The Prussian infantry could nothing but impotently fire ineffectual volleys to their front, as the voltigeurs aimed and shot at a mass that they couldn’t miss.

By 11 am, both the literal and figurative fog of war crippled both sides ability to understand what was happening. Hohenlohe, with orders not to become decisively engaged, knew he had lost a division, but only had light infantry to his front and no idea where the French main body was, or even if it was nearby. With less than 30,000 men under his command, he needed to be sure what was in front of him, lest he be flanked and destroyed. Napoleon had three full corps coming on line, Soult, Lannes, and Augeraeau, the Imperial Guard (corps equivalent) in reserve with Murat’s cavalry corps and Ney’s corps moving into position. Nevertheless, the fog prevented Napoleon and his commanders from understanding what they faced. The integral corps cavalry was desperately groping about in the fog trying to find more Prussian infantry than the 30,000 or so opposite Vierzehnheilegen. Lannes, in the center, attempted to shake things up around the town by probing the Prussian line, but was repulsed. In the fog, Napoleon couldn’t commit his now 96,000 man army until he knew where the Prussian main body was. He assumed it was close, not marching north away from Jena.

The Battle of Jena was at an impasse. The late autumn Central European fog, which didn’t seem to dissipate in the midday sun, gave the battlefield an otherworldly glow. In the bright fog, Napoleon couldn’t attack until he found the Prussian main body and Hohenlohe couldn’t attack because he wasn’t the Prussian main body. The Grande Armee continued to arrive.

Ney’s VI Corps was the Grande Armee’s rear guard and the last to arrive at Jena. Augereau was shifting to face the Saxon division idling at Innerstedt on Hohenlohe’s far right. The situation in front of Vierzehnheilegen was chaotic but the Saxons were a tangible threat. Augereau didn’t know that the Saxons didn’t have the propensity move. They weren’t in the best of spirits, their supply lines were cut with Leipzig and the Prussian supply trains were in administrative chaos. The Saxons were last in priority. In accordance with the gentlemanly rules of 18th century limited warfare, the Saxons and Prussians were forbidden to forage. Some of the Saxon regiments hadn’t eaten in two days. They were content to hold Innerstedt and allow Augereau to build up to their front.

Marshal Ney arrived with his advanced guard and cavalry ahead of his main body about 10 am, leaving his infantry to come up as fast as they could. He was seething to get into battle. Napoleon told him to place his corps to the right of Lannes in the gap with Soult. But Lannes and Soult were already in contact, Napoleon just couldn’t tell in the fog. So Ney rode over the battlefield looking for a place for his corps, he found one in the gap between Augereau and Lannes south of Vierzehnheilegen. Without telling Napoleon, he rode directly for the ground he unilaterally decided his corps was to occupy.

The fog induced stalemate would shortly end at the hands of Napoleon’s fiery red headed marshal.

As Augereau shifted, the impetuous Ney took his cavalry forward and immediately got mixed up in the light infantry fight in front of the town. Most of his corps was still marching through Jena, while his cavalry was cutting and slashing its way through the fog. One chasseur squadron broke a Prussian cavalry squadron covering several batteries of artillery firing on the town, and then turned the guns on the Prussian line. The Prussian line was ordered to fire on the cavalrymen, the disorganized Prussian cavalry and the French cavalry looked similar in the fog, and many Prussians refused to fire. They had standing orders to fire on any Prussian “deserters” but the French cavalry that looked like Prussians weren’t deserting, and the retreating Prussians weren’t obviously deserting. No one could tell where the artillery was coming from, whether their own captured guns, or French guns in the distance. And all of that with the simple reality that death could emerge from the mist at any time, and regularly did so to their comrades all around them. The situation was massively confusing for Prussians.

The confusion caused by Ney’s aggressive “reconnaissance” of his self appointed position in the line had two major effects. First, the entirety of the Prussian cavalry was neutralized. To avoid further confusion, Hohenlohe moved his squadrons into the line, as if they were infantry. The cavalry was ill-suited to the task of static defense, but were easily controlled, extended his line further, and could be used to clear light infantry when the Prussian line advanced. Ney’s provocation convinced Hohenlohe he had to stabilize the Vierzehnheilegen situation or he wouldn’t have any officers left. The Prussian Army was uniquely dependent on officers to control the men. Hohenlohe realized the need to act or the situation would spiral out of control and his command would be destroyed in the fog by light infantry and cavalry. He decided to attack. He ordered his cannon to fire incendiaries on the town to prevent the French from turning each building into a stronghold. And once the town was in a significant conflagration, he ordered his command to advance and clear everything to their front.

The order to advance was welcomed by the Prussian line. For two hours they impotently fired ineffectual volley after ineffectual volley into the mist toward the town to no noticeable effect on French fire. The flames in the village and the Prussian advance forced the French light infantry and cavalry to withdraw and an eerie calm descended on the battlefield. It wouldn’t last.

The first reports of the Prussian advance flowed up the Dornberg Heights to a relieved Napoleon who spent the last several hours anxiously scanning the horizon for a glimpse of the Prussian main body. The Prussians wouldn’t advance without the main body, or so Napoleon’s believed. Not wanting to hand the Prussians the initiative, he ordered all of his corps to attack.

Nearly 50,000 Frenchmen crashed into 30,000 Prussians and Saxons in the fog. Ney with his vanguard and cavalry were briefly cut off. It was neither the first time nor the last time Ney would be surrounded; he formed a square and waited out the Prussian attack, fully confident that Napoleon would soon attack and save him. Ney’s faith in Napoleon was well founded.

The French and Prussian attacks devolved into a long firefight as neither side had the mass of men to break each other’s lines. Both Napoleon and Hohenlohe were waiting on more men to arrive on the battlefield. Napoleon’s arrived first. The bulk of Soult’s Corps and entirety of Ney’s infantry divisions arrived with Murat’s cavalry close behind. The Prussian reserves were still on the road from Weimar, miles away. The influx of men gave Napoleon another 50,000 troops to push into the attack. He ordered all commanders forward, and all reserves forward but the Imperial Guard.

The standard three deep line, three lines deep Prussian closed line formation could fire at most two rounds before the massed French columns, some battalions 20 men deep, were upon them. Moreover, the French line overextended the Prussian. Soult in the north on the French right quickly routed those to his front. He was struck in the flank by the remains of Holtzensdorff’s force that Lannes defeated earlier, but a timely charge by his light cavalry routed them again. Instead of pursuing the twice defeated Holtzendorff, Soult turned towards Vierzehnheilegen to envelope Hohenlohe’s attack.

In the center, Napoleon, ever the artilleryman, personally commanded the grand battery that blasted massive holes in the astonished Prussians. Augereau ground down the Saxon division at Innerstedt to his front. Lannes pushed forward and retook Vierzehnheilegen. The Prussian infantrymen, and their Saxon little brothers, retired with discipline when they could, and their famed reloading drill caused quite a bit of damage. Though outdated, Prussian tactics and harsh discipline could still show its best in the defense. But faced with overwhelming numbers and firepower, the Prussian line had no choice but to give way. Sensing weakness, Murat ordered his recently arrived heavy cavalry into the attack. The Prussian and Saxon lines broke.

Advancing west, the French juggernaut was stopped briefly at Gross Romstedt by the 15,000 strong Prussian reserve under General Ernst Ruechel which was slowly on its way from Weimar at the request of Hohenlohe. A Prussian’s Prussian, Ruechel chose to attack the massive force to his front. Lannes quickly brought up his cannon and shot massive holes in Ruechel’s lines as his and Soult’s infantry flanked flowed around them. When Ruechel attempted to withdraw, Lannes’ eager light cavalry turned it into a rout.

About this time, Napoleon finally realized that he hadn’t faced the Prussian main body under the Duke of Brunswick, but just Hohenlohe’s strong detachment.

The Duke of Brunswick was 30 kilometers away, in the midst of his own battle, where he outnumbered his French opponent nearly three to one.