Which 1812 battle was a decisive victory for Wellington over Marshal Marmont in Spain?

The 1812 battle that was a decisive victory for Wellington over Marshal Marmont in Spain was the Battle of Salamanca.

Fought on July 22, 1812, near Salamanca during the Peninsular War, the battle pitted Wellington’s Anglo-Portuguese army against Marmont’s French Army of Portugal. Marmont attempted to outflank the Allied force but stretched his formations along a ridge, creating a vulnerable separation between his divisions. Wellington recognized the mistake and launched powerful attacks against the exposed French left.

Marmont and his second-in-command, General Bonet, were wounded early in the fighting. Bertrand Clauzel assumed command and mounted a counterattack, but the French army was eventually routed. Allied losses were roughly 5,200, while French losses—including prisoners—were around 13,000, although estimates vary.

The victory had major consequences. Wellington entered Madrid on August 6, 1812, and the French abandoned Andalusia. Albuera, Talavera, and Vitoria were also important Peninsular War battles, but they do not fit the question: Albuera was fought in 1811, Talavera in 1809, and Vitoria in 1813.