Which 1808 battle forced a French corps to surrender to Spanish forces in Andalusia?

The 1808 battle that forced a French corps to surrender to Spanish forces in Andalusia was the Battle of Bailén.

Fought from 16 to 19 July 1808 near Bailén in Jaén province, the battle pitted the Spanish Army of Andalusia under Francisco Javier Castaños against the French 2nd Gironde Observational Corps commanded by Pierre Dupont de l’Étang. Spanish forces trapped Dupont’s troops between converging formations and repeatedly repelled French attempts to break through.

The heat, lack of water, illness, and separation from supporting forces badly weakened the French. Dupont eventually opened surrender negotiations. He agreed to capitulate not only his own force but also General Dominique Vedel’s division, even though Vedel’s troops were outside the main Spanish encirclement. About 17,000 French soldiers were captured.

Bailén was the first major open-field defeat of a Napoleonic army and the worst French defeat of the Peninsular War at that point. News of the surrender forced Joseph Bonaparte’s regime to retreat from Madrid toward the Ebro. The battle is sometimes written “Baylen” in English, but Bailén is the standard modern form.