On the 4th the army was on the move by two o'clock in the morning. A bright moon was shining and, by its light, it was discovered that the enemy had shifted his position for one much stronger, with approaches protected by patches of wood and bog. The Prussian army therefore marched back to their camp, the king hoping that, being so far from their base of supplies, the enemy would be forced ere long to make some movement that would afford him a chance of attacking them under better circumstances.
The ground from Weissenfels rises, very gradually, to a height of a hundred and twenty feet or so; which in so flat a country is regarded as a hill. On this slight swelling are several small villages. Of these Rossbach is the principal, standing high up on its crest. Here Frederick's right wing was posted, while his left was at Bedra. The king took up his quarters at a large house in Rossbach; and from its roof, at eight o'clock on the morning of the 5th, he saw that the enemy were getting into motion and moving away towards their left.
The movement had begun much earlier. Half an hour later they had passed through the village of Grost, and were apparently making their way to Freiburg, where they had some magazines. Hoping to have a chance of attacking their rear, Frederick ordered the cavalry to saddle, and the whole army to be in readiness, and then sat down to dinner with his officers at noon. Little did he dream, at the time, that the slow and clumsy movement that he was watching was intended, by the enemy, to end in a flank attack on himself.
On the previous day Soubise, with his generals, looking down on the Prussian camp, had reckoned their force at ten thousand. In reality they had seen only a portion of their camp, the site being hidden by a dip of the ground. Even Soubise thought that, with the odds of over five to one in his favour, he could fight a battle with a certainty of success; and planned a masterly march, by which he would place himself on Frederick's left and rear, drive him into the bend made by the Saale, and annihilate his army. In his enthusiasm at this happy idea, he sent off a courier to carry the news, to Versailles, that he was about to annihilate the Prussian army, and take the king prisoner.
Frederick's dinner was prolonged. There was nothing to be done, and patience was one of the king's strong points. At two o'clock an officer, who had remained on watch on the housetop, hurried down with news that the enemy had suddenly turned to the left. The king went up to the roof with his officers, and at once divined the intention of his foes.
It was a glorious moment for him. At last, after three weary months, he was to meet them in battle. Instantly his orders were given, and in half an hour the Prussian army was all in movement, with the exception of some irregular corps which were left to occupy the attention of the enemy's horse, which had been posted as if to threaten Rossbach. By the line taken, the Prussians were at once hidden behind the crest of the hill from the enemy; and so Soubise thought that the Prussians, being afraid of his attack, were marching away with all speed for Keith's bridge at Merseburg. He accordingly hurried on his cavalry, and ordered the infantry to go at a double, for the purpose of capturing the runaway Prussians.
In the meantime Seidlitz, with four thousand horse, trotted briskly along until he reached, still concealed from the enemy's sight, the spot towards which they were hurrying, in two great columns headed by seven thousand cavalry. He allowed them to move forward until he was on their flank, and then dashed over the crest of the hill, and charged like a thunderbolt upon them.
Taken completely by surprise, the enemy's cavalry had scarce time to form. Two Austrian regiments and two French were alone able to do so. But there was no withstanding the impetus of the Prussian charge. They rode right through the disordered cavalry; turned, formed, and recharged, and four times cut their way through them, until they broke away in headlong flight; and were pursued by Seidlitz until out of sight from the hill, when he turned and waited, to see where he could find an opportunity of striking another blow.
By this time Frederick, with the infantry, was now pouring over the crest of the hill, their advance heralded by the fire of twenty-four guns. Rapidly, in echelon, they approached the enemy. In vain Soubise endeavoured to face round the column, thus taken in flank, to meet the coming storm. He was seconded by Broglio and the commander of the Confederate army, but the two columns were jammed together, and all were in confusion at this astounding and unexpected attack. Orders were unheard or disobeyed, and everything was still in utter disorder, when six battalions of Prussian infantry hurled themselves upon them.
When forty paces distant, they poured in their first terrible volley, and then continued their fire as fast as they could load; creating great havoc among the French troops on whom they had fallen, while away on each flank the Prussian artillery made deep gaps in the line. Soon the mass, helpless under this storm of fire, wavered and shook; and then Seidlitz, who had been concealed with his cavalry in a hollow a short distance away, hurled himself like a thunderbolt on their rear, and in a moment they broke up in headlong flight. In less than half an hour from the first appearance of the Prussians on the hill, the struggle had ended, and an army of from fifty to sixty thousand men was a mob of fugitives; defeated by a force of but twenty-two thousand men, not above half of whom were engaged.