At the Battle of Eylau in February 1807, he led his dragoons in Murat's famous 10,000-man cavalry charge depicted by Jean Antoine Siméon Fort, the 19th century history painter. At the Battle of Wagram (July 1809) Walther commanded four squadrons of Grenadiers à Cheval of Jean-Baptiste Bessières's Imperial Guard Cavalry. As the battle was turning to the Austrians' favour, Bessières launched a massive cavalry charge with the combined elements of the Cavalry Reserve Corps and the cavalry of the Imperial Guard. After a first, precipitated charge, Bessières was wounded and incapacitated, and the whole cavalry attack was suspended. Napoleon then launched a major infantry attack with Jacques MacDonald's infantry and considerable cavalry support, including the Guard cavalry under Walther. After the battle, MacDonald accused Walther of failure to mobilize his cavalrymen quickly enough and not charging when the time was right. Walther accompanied Napoleon to Russia as a commander of the light cavalry of the Imperial Guard, part of which rotated duties as Napoleon's honor guard.