The battle began on the right and left and the conflict proved terrible. Davoust, in particular, was placed in a situation sufficient to try a man of the most determined courage and firmness but Bernadotte refused to support him. He paraded around Apolda, while 26,000 French troops were engaged with 60,000 picked men, commanded by the Duke of Brunswick and the King of Prussia. Thus, says General Gourgaud, he caused the death of five or six thousand Frenchmen and hazarded the success of the day, for which he experienced a very short disgrace. Napoleon on this occasion observed that Bernadotte did not behave well, and that he would have felt gratified had Davoust been defeated; "but," added the Emperor, "the affair reflects the highest honor on the conqueror, and the more so, as Bernadotte rendered his situation a most difficult one." Bernadotte's conduct was such that a decree was signed by Napoleon that must have resulted in his being shot, but out of regard to his wife the Emperor destroyed the order the moment he was about to put it into the hands of one of his officers.
A hand to hand struggle followed the first charge of the Prussians. It was received by Soult and was a doubtful engagement until Ney appeared with a fresh division and drove the Prussians back. Nothing but the smoke of battle now obstructed the view, the famous sun of Napoleon having mounted the heavens was throwing a flood of light on a terrific engagement. Charge after charge followed, both sides maintaining their positions with firmness and valor. The commanders were constantly executing manoeuvres as though on parade. At one time the Emperor observed Ney, whom he had supposed to be in the rear, engaged with the Prussians. He hastened up greatly displeased, but on discovering the brave marshal defending himself in the centre of two weak squares against the whole of the Prussian cavalry, his displeasure gave way to admiration, and an immediate relief was ordered and brought up by Bertrand and Lannes. During the time that elapsed before relief arrived he fought as intrepidly as before, and was not in the least disconcerted by his hazardous position. Davoust's plans were so well laid, and his generals and troops displayed such courage and skill, that Blucher, with 12,000 cavalry, had not the satisfaction of penetrating through a single company. The king, the guards, and the whole army, attacked the French without obtaining better success. Amidst the deluge of fire that surrounded them on all sides, they preserved all their national gaiety. A French soldier, nick-named "the Emperor" impatient at the obstinacy of the Prussian guards, exclaimed, "On with me, grenadiers! Come, follow the Emperor!" when, rushing into the thickest of the battle, the troops followed, and the enemy was penetrated. For this deed he was raised to the rank of a corporal.
Napoleon, field-glass in hand, at length ordered a general onslaught all along the lines, to be followed by a bold charge of Murat's cavalry at a point where the Emperor had detected a weakness in the enemy's lines. As the signal blast for advancing was sounded, the eager squadrons that had been smelling the smoke of battle for hours with impatience, rushed onward to glory or to death. On, on they charged with all the vehemence and impetuosity of the French cavalryman, each of whom believed that on him, and him alone, rested the fate of the day, and as on so many similar occasions, they were victorious. The sturdy Prussian columns were broken,—infantry, cavalry, guards and grenadiers were mowed down by thousands. The French infantry gave fresh proof of their valor and sustained their reputation at this engagement. In one of the charges which the divisions under Morand had to sustain from the numerous Prussian cavalry under Prince Henry, the 17th regiment, before presenting arms, placed their caps at the ends of their bayonets, crying, "Vive l'Empereur!" "Why not fire then?" exclaimed Colonel Lanusse who apprehended the enemy would be upon them before they were ready. "Oh, time enough for that" they replied, "at fifteen paces you shall see." In fact a murderous discharge at that distance made the Prussians turn their horses' heads and retire.
The ardor of the troops on this important day was such that some corps, which circumstances prevented from taking part in the engagement, loudly expressed their dissatisfaction. One of these traits is sufficiently characteristic of the soldier and the Emperor under whose eyes they fought. At an early period of the conflict, while the French cavalry was anxiously expected, Napoleon seeing his infantry wings in a state of agitation, being threatened by the enemy's cavalry, set off at a full gallop to direct the manoeuvres and change the front into squares. The infantry of the imperial guard, seeing all the rest of the troops engaged, while the Emperor left them in inaction, many voices were heard to cry "Forward!" "Who is that?" asked the Emperor quickly, as he presented himself in front of the battalions; "This is some beardless young man, who wishes to anticipate what I intend to do. Let him wait until he has commanded in thirty pitched battles, before he pretends to give me advice."
Out of the 70,000 Prussians who had appeared on the field of battle, not a single corps remained entire, not one retreated in order. Out of the 100,000 French, composed of the corps of Marshals Soult, Lannes, Augereau, Ney, Murat and the Guard, not more than 50,000 had fought, and they had been sufficient to overthrow the Prussian army.
This rout ended in the complete breaking up of the Prussian army, horse and foot all flying together, in the confusion of panic, upon the road to Weimar. At that point the fugitives met and mingled with their brethren, flying as confusedly as themselves, from Auerstadt.
In his account of the battle of Jena Napoleon spoke with pleasure of the enthusiasm shown by his soldiers during the heat of battle. In conclusion he said: "In so warm a fight, in which the enemy lost almost all their generals, we should thank that Providence which watched over our army, that no man of note has been killed or wounded. Marshal Lannes had his breast scratched without being wounded. Marshal Davoust had his hat carried away and a great number of balls in his clothes." To Josephine, who was awaiting the results of the campaign at Mayence, he wrote on October 16th: "Everything has turned out as I planned, and never was an army more thoroughly beaten and destroyed." The Emperor confessed, that, during the night before the battle of Jena, he had been exposed to the most imminent danger, and might have disappeared without anyone knowing clearly his fate. He had approached the bivouacs of the Prussians in the dark, to reconnoitre, having only a few officers about his person. The French army was almost everywhere on the alert, under a persuasion that the Prussians were strongly addicted to nocturnal attacks. Returning from that survey, the Emperor was fired at by the first sentinel of his own camp, which proved a signal for the whole line; and he had no resource left but to throw himself flat on his face until the mistake should be discovered. His principal apprehension, however, was not realized; he feared least the Prussian line, then very near him, might act in the same manner.
When the conflict ended 20,000 Prussians lay dead on the battle field, or were taken prisoners, including twenty generals. Among the trophies of war were 300 cannon and sixty royal standards.
The Queen of Prussia was a fearless horsewoman and had faced great dangers at Jena. When she rode before her troops in her helmet of polished steel, shaded by a plume, in her glittering golden cuirass, her tunic of silver stuff, her red boots with gold spurs, she resembled Tasso's heroines. The soldiers burst into cries of enthusiasm as they saw their warlike queen: before her were bowed the flags she had embroidered with her own hands and the old, torn, and battle-stained standards of Frederick the Great. After the battle she was obliged to take flight, at full gallop, to avoid being captured by the French hussars.