The Battle of Bailén was fought in 1808 between the Spanish Army's Army of Andalusia, under General Francisco Javier Castaños and the French Imperial Army's 2nd Gironde Observational Corps under Divisional-General Pierre Dupont de l'Étang. The first open-field defeat of a Napoleonic army, the battle's heaviest fighting took place near Bailén, a village by the Guadalquivir river in the Jaén province of southern Spain.