Battle of Jena–Auerstedt
The duke commanded the large Prussian army at Auerstedt during the double Battle of Jena–Auerstedt on 14 October 1806. His forces were defeated by Napoleon's marshal Davout, despite the Prussians outnumbering the French around Auerstedt by two to one. During the battle he was struck by a musket ball and lost both of his eyes; his second-in-command Friedrich Wilhelm Carl von Schmettau was also mortally wounded, causing a breakdown in the Prussian command. Severely wounded, the Duke was carried with his forces before the advancing French. He died of his wounds in Ottensen on 10 November 1806.