ORDER OF BATTLE // July 16, 1808
Battle of Bailén
Estimated force strength by side, with confidence labels per surviving record.
Forces engaged
2 sides catalogued · combined 49,770–54,430 estimated
Spain
29,770–30,000
Medium-confidence figure
France
20,000–24,430
Medium-confidence figure
Battle context
The Battle of Bailén marked the first open-field defeat of a Napoleonic army, a result that carried immediate strategic and psychological consequences across Europe. Spain's Army of Andalusia under Castaños, numbering roughly 30,000 troops, forced the French 2nd Gironde Observational Corps under Dupont, estimated at up to 24,000, to suffer around 3,000 casualties against Spanish losses of approximately 1,000. The outcome demonstrated that French Imperial forces were not invincible in conventional pitched battle, undermining the aura of Napoleonic military supremacy that had dominated European affairs since the mid-1790s. Within the Peninsular War, Bailén halted French consolidation in southern Spain and signaled to other European powers that organized resistance could produce results, reinforcing the broader Coalition effort against Napoleon's imperial ambitions.
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