was disappointed that the British remained neutral. His initial advance into France was slowed by poor weather, the rough terrain of the Forest of Argonne, and an outbreak of dysentery among his troops. The Duke was less successful against the French citizens' army that met him at Valmy. Having secured Longwy and Verdun without serious resistance, he turned back after a mere skirmish in Valmy, and evacuated France. Initially the Duke intended to winter in the fortress of Verdun, before resuming the campaign in France the following spring. However, Kellerman's forces outflanked him by advancing up the Rhine, recapturing French possessions there. The Duke abandoned Verdun on 8 October and Longwy on 22 October, before retreating back into Germany. When he counterattacked the Revolutionary French who had invaded Germany, in 1793, he recaptured Mainz after a long siege, but resigned in 1794 in protest at interference by Frederick William II of Prussia. War of the Fourth Coalition Prussia did not take part in the Second Coalition or Third Coalition against Revolutionary France. However, in 1806 Prussia declared war on France, beginning the War of the Fourth Coalition. Despite being over 70 years old, the Duke of Brunswick returned to command the Prussian army at the personal request of Louise, Queen of Prussia. By this stage the Prussian army was regarded as backward, using outdated tactics and with poor communication. The structure of the high command has been particularly criticised by historians, with multiple officers developing differing plans and then disagreeing on which should be followed, leading to disorganisation and indecision. 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. The duke's body was provisionally laid to rest in the Christianskirche at Ottensen in 1806. It was later transferred for reburial in Brunswick Cathedral on 6 November 1819. Family On 16 January 1764, Charles married Princess Augusta of Great Britain, eldest sister of