The battle of Saalfeld (10 October 1806) was the first major clash during the War of the Fourth Coalition and saw a French column defeat a smaller Prussian force under Prince Louis Ferdinand
Prince Louis Ferdinand was the commander of the Advance Guard Division of Hohenlohe's army, the left (or eastern) part of the main Prussian army. Hohenlohe had been in favour of an eastern line of advance for the Prussians, but had been overruled in favour of the Duke of Brunswick's plan for an advance further to the south-west. The Prussian plans were disrupted by Napoleon, who on 8 October began to cross the wooded hills of the Thüringerwald. On 9 October Brunswick decided to concentrate west of the Saale, with his army to the north and Hohenlohe to the south. Prince Louis was posted at Saalfeld, where he formed the southern advance guard of the army. On the night of 9-10 October the Prince reported seeing French camp fires to his south.
That night Hohenlohe decided to prepare to cross the Saale, and issued orders to Prince Louis with that in mind. Unfortunately the Prince misinterpreted his orders to mean that Hohenlohe was actually going to cross the river, while the Duke of Brunswick moved east from Erfurt towards Auma (north of Saalfeld). Prince Louis had four Prussian and six Saxon infantry battalions, ten cavalry squadrons and 44 guns, a total of around 8,300 men.
On the morning of 10 October the first corps in the left-hand French column reached Saalfeld. This was Lannes' V Corps, which had got some way ahead of Augereau's corps. Lannes had well over twice as many men as the Prussians, but his men were emerging in order of march, so at first Suchet's division had to face the Prussians almost alone.
As the French emerged from the hills at about 10am Lannes decided to attack. His skirmishers and the first infantry battalion were sent to pin the Prussians in place. The next troops to arrive were sent north-west through the woods to take up a position on Prince Louis's right flank. This would threaten his lines of communication with the rest of the army.
At about 11am Prince Louis received new orders. Hohenlohe had been forbidden to cross the Saale, and so Prince Louis was ordered to retire to Rudolstadt and not to attack the French. An hour earlier this order might have saved the prince, but now his army was too closely engaged to easily withdraw.
At about the same time the Prince decided to reinforce his right wing, to prevent the French from cutting him off. The fighting focuses on the villages of Beulitz and Croesten and a low ridge called the Sandberg.
The fighting was quite even until about one in the afternoon. At this point Prince Louis ordered his Saxons to attack the French skirmishers in the centre. This attack failed, and the French launched a counterattack which threated the entire Prussian position. Prince Louis decided to lead five squadrons of cavalry into the fighting in an attempt to restore the situation. The French cavalry responded, and the Prince was killed in hand-to-hand combat with Quartermaster Guindet of the 10th Hussars.
With their commander dead the Prussian force collapsed. The survivors escaped across the Saale, but didn't rally until they were four miles to the north. The French captured 1,500-1,800 prisoners and 33 guns, at a cost of only 172 killed and wounded. Prussian morale was badly affected by both the defeat and by the death of Prince Louis, who was considered to be one of the best Prussian commanders, despite his lack of experience. The feeling of invincibility that had pervaded the Prussian army began to evaporate and a sense of panic began to replace it. Brunswick decided to retreat north, but he was caught at Jena and Auerstädt on 14 October and suffered two heavy defeats.