The Prussian camp on the morning of 5 November 1757 lay between Rossbach (left) and Bedra (right), facing the Allies, who, commanded by the French general, Charles de Rohan, prince de Soubise (1715 - 1787), and Joseph Frederick William, duke of Saxe-Hildburghausen (1702 - 1787), General Feldzeugmeister of the Empire, had manoeuvred in the preceding days without giving Frederick an opportunity to bring them to action, and now lay to the westward, with their right near Branderoda and their left at Mücheln. The advanced posts of the Prussians stood in the villages immediately west of their camp, those of the Allies on the Schortau hill and the Galgenberg.
The Allies (about 42,000 men) possessed a numerical superiority of two to one in the battle itself, irrespective of detachments, and their advanced post overlooked all parts of Frederick's camp. They had had the best of it in the manoeuvres of the previous days, and the duke of Hildburghausen determined to take the offensive. He had some difficulty, however, in inducing Soubise to risk a battle, and the Allies did not begin to move off their camping-ground until after eleven on the 5th, Soubise probably having the intention to engage as late in the day as possible, with the idea of gaining what advantages he could in a partial action. The plan called for the Allied army to march by Zeuchfeld, round Frederick's left (which no serious natural obstacle covered), and to deploy in battle array, facing north, between Reichardtswerben (right) and Pettstädt (left). The duke's proposed battle and the more limited aim of Soubise appeared equally likely to succeed in taking this position, which threatened to cut off Frederick from the towns on the Saale. But the Allies could only attain this position by marching round the Prussian flank, i.e. by a flank march before the enemy. The Allies posted a considerable flank guard against the obvious risk of interference on the exposed flank. Not the execution of their original design, but a hasty modification of it to suit unfounded assumptions caused the Allies to meet with disaster.
Frederick spent the morning watching them from a house-top in Rossbach. The initial stages of their movement convinced him that the Allies had started retreating southward towards their magazines, and about noon he went to dinner, leaving Captain von Gaudi on the watch. This officer formed a different impression of the Allies' intentions, for the columns which from time to time became visible in the undulations of the ground appeared to turn eastwards from Zeuchfeld. Gaudi's excited report at first served only to confirm Frederick in his error. But when the king saw for himself that hostile cavalry and infantry had already approached near to Pettstädt, he realized the enemy's intentions. The Allies now offered him the battle for which he had manoeuvred in vain, and he took it without hesitation.
Leaving a handful of light troops to oppose the French advanced post (or flank guard) on the Schortau hill, the Prussian army broke camp and moved -- half an hour after the king gave the order -- to attack the enemy. The latter were marching in the normal order in two main columns, the first line on the left, the second line on the right; farther to the right marched a column consisting of the reserve of foot, and between the first and second lines was the reserve artillery on the road. The right-wing cavalry was of course at the head, the left-wing cavalry at the tail of the two main columns. At first they rertained regulation distances, but when wheeling eastward at Zeuchfeld much confusion arose, part of the reserve infantry getting in between the two main columns and hampering the movements of the reserve artillery, and the rest, on the outer flank of the wheel, found themselves unable to keep up with the over-rapid movement of the wheeling pivot. A weak flank guard was thrown out towards Rossbach. When it was seen that the Prussians were moving, as far as could be judged, eastward, it was presumed that they were about to retreat in order to avoid being taken in flank and rear; and the Allied generals thereupon hurried the march, sending on the leading (right-wing) cavalry towards Reichardtswerben, and calling up part of the left-wing cavalry from the tail of the column, and even the flank-guard cavalry, to take part in the general chase.
That Frederick's move meant an attack upon them before they could form up, Soubise and the duke failed to realize. They had taken more than three hours to break camp, and found it difficult to suppose that Frederick's army could move off in one-sixth that time. It seemed obvious, moreover, that the Prussians were not deploying for battle on the plain in front of Rossbach and Nahlendorf.
Frederick had no intention either of forming up parallel to the enemy or of retreating. As his army could move as a unit twice as fast as the enemy's, he intended to make a detour, screened by the Janus Hugel and the Pölzen Hugel, and to fall upon them suddenly from the east. If at the moment of contact the Allies had already formed their line of battle facing north, the attack would strike their right flank; if they were still on the move in column eastwards or north-eastwards, the heads of their columns would be crushed before the rest could deploy in the new direction -- deployment in those days being a lengthy affair. To this end General von Seydlitz, with every available squadron, hurried eastward from Rossbach, behind the Janus Hugel, to the Pölzen Hugel; Colonel von Moller, with eighteen heavy guns, came into action on the Janus Hugel at 315 against the advancing columns of the Allied cavalry; and the infantry followed as fast as possible.
When they came under the fire of Moller's guns, the Allied squadrons, which now lay north of Reichardtswerben and well ahead of their own infantry, suffered somewhat heavily; but it was usual to employ heavy guns to protect a retreat, and they contented themselves with bringing some fieldguns into action. They were, however, amazed when von Seydlitz's thirty-eight squadrons suddenly rode down upon the head and right flank of their columns from the Polzen Hugel avec une incroyable vitesse. Gallantly as the leading German regiments deployed to meet him, the result was scarcely in doubt for a moment. Von Seydlitz threw in his last squadron, and then himself fought like a trooper, receiving a severe wound. The melée drifted rapidly southward, past the Allied infantry, and von Seydlitz finally rallied his horsemen in a hollow near Tagewerhen, ready for fresh service. This first episode took only half an hour, and by that time the Prussian infantry, in echelon from the left, was descending the Janus Hugel to meet the already confused and disheartened infantry of the Allies.
The latter, as their cavalry had done, managed to deploy some regiments on the head of the column, and the French in particular formed one or two columns of attack -- then peculiar to the French army -- and rushed forward with the bayonet. But Moller's guns, which had advanced with the infantry, tore gaps in the close masses, and, when it arrived within effective musketry range the attack died out before the rapid and methodical volleys of the Prussian line.
Meanwhile the Allies tried in vain to form a line of battle. The two main columns had got too close together in the advance from Pettstädt, part of the reserve which had become entangled between the main columns was extricating itself by degrees and endeavouring to catch up with the rest of the reserve column away to the right, and the reserve artillery proved useless in the middle of the infantry. The Prussian infantry was still in echelon from the left, and the leftmost battalions that had repulsed the French columns quickly came within musket-shot of this helpless mass. A few volleys directed against the head and left flank of the column sufficed to create disorder, and then from the Tagewerben hollow von Seydlitz's rallied squadrons charged, wholly unexpectedly, upon its right flank.
The Allied infantry thereupon broke and fled. Soubise and the duke, who had received a wound, succeeded in keeping one or two regiments together, but the rest scattered over the countryside. The battle had lasted less than an hour and a half, and the last episode of the infantry fight no more than fifteen minutes. Seven Prussian battalions only had engaged with the enemy, and these expended five to fifteen rounds per man.
Von Seydlitz and Prince Henry of Prussia, the cavalry and the infantry leaders engaged, each received wounds, but the total losses amongst the Prussian army comprised under 550 officers and men, as compared with 7,700 on the part of the Allies.
Original text from 1911 Encyclopaedia Britannica