In 1866, during the Austro-Prussian War between the Kingdom of Prussia and the Austrian Empire, Wilhelm assumed command of the Baden Division of the 8th Federal Corps (German: 8.
Bundeskorps) siding with the Austrian-led German Confederation.
The dissolution of the 8th Federal Corps began on 30 July 1866 when Wilhelm sent a flag of truce along with a letter to the Prussian headquarters at Marktheidenfeld.
The letter stated that Wilhelm's father Leopold, Grand Duke of Baden, had entered into direct negotiations with Wilhelm I of Prussia and that King Wilhelm I granted the Baden troops permission to return to their homes.

Immediately following the Austro-Prussian War, Wilhelm reformed the army of Baden based upon the Prussian system.
Wilhelm and Prince August of Württemberg were the two south German princes who were foremost in securing the union of the Northern and Southern German states.
On 22 September 1868, Wilhelm announced his resignation from the command of the troops of the Grand Duchy of Baden and was replaced by General Beza.
In 1866, during the Austro-Prussian War between the Kingdom of Prussia and the Austrian Empire, Wilhelm assumed command of the Baden Division of the 8th Federal Corps (German: 8. Bundeskorps) siding with the Austrian-led German Confederation. The dissolution of the 8th Federal Corps began on 30 July 1866 when Wilhelm sent a flag of truce along with a letter to the Prussian headquarters at Marktheidenfeld. The letter stated that Wilhelm's father Leopold, Grand Duke of Baden, had entered into direct negotiations with Wilhelm I of Prussia and that King Wilhelm I granted the Baden troops permission to return to their homes.
Immediately following the Austro-Prussian War, Wilhelm reformed the army of Baden based upon the Prussian system. Wilhelm and Prince August of Württemberg were the two south German princes who were foremost in securing the union of the Northern and Southern German states. On 22 September 1868, Wilhelm announced his resignation from the command of the troops of the Grand Duchy of Baden and was replaced by General Beza.
Prince William of Baden (1829–1897)