Napoleon had arranged the Grande Armée into three columns to cross the Thuringian Forest to attack the Prussian-Saxon army.

[5] At 5 am on 10 October, Lannes with Louis-Gabriel Suchet's division and Anne-François-Charles Trelliard brigade of light cavalry of V corps began advancing down the road to Saalfeld, aware that a Prussian-Saxon force was in front of them.

In the evening of 9 October Oberst Leopold Ludwig Maximilian Nordeck zu Rabenau (who commanded a detachment at Saalfeld) reported to Prince Louis that a French column of between 16,000 and 20,000 men had left Coburg heading for Saalfeld and that a post of 30 hussars stationed at Gräfenthal and the Jäger Company "Valentini" stationed at Hoheneiche [de] had both retreated to Arnsgereuth after clashing with the French.

[8] During 9 October a fusilier company commanded by August von Gneisenau was sent to Arnsgereuth to support the troops there, and having confirmed that the French were advancing on Saalfeld and in strength, the Prussian troops withdrew from Arnsgereuth to Lerchenhügel [de], just outside Saalfeld, with advance posts in Garnsdorf [de].

[11] As the French troops advanced and the Prussian-Saxon army prepared to fight them, Marshal Lannes noticed that the right flank of the Prussian-Saxon army was completely uncovered, and while the cavalry and French advanced guard engaged the Prussians around Garnsdorf and Saalfeld, he ordered rest of Suchet's division to march northwards through the woods to outflank the Prussian and Saxon line.

[13] He also ordered the "Prince Xaver" and "Kurfürst" regiments to take the offensive by attacking the plain between Siechentbal and the Kesselthal streams.

Order in the Prussian and Saxon cavalry began to break down, and they fled joining the troops retreating from Saalfeld.

As the first battalion of the "Prince Clemens" Regiment moved down the slope it was attacked repeatedly by the 21st Chasseurs à Cheval, and the Saxons broke under the onslaught.

After four days of further marches, the French engaged the Prussians and Saxons at the twin battles of Jena and Auerstedt on the plateau west of the river Saale.

The plaque reads "Here Prince Louis Ferdinand of Prussia fell fighting for his grateful Fatherland on 10 October 1806".