Which 1811 battle of the Peninsular War is often described as the bloodiest?

The Battle of Albuera was fought on May 16, 1811, and is often described as the bloodiest battle of the Peninsular War.

Near the Spanish village of Albuera, an Allied force of British, Portuguese, and Spanish troops under William Beresford fought Marshal Nicolas Soult’s French Army of the South. Soult was trying to relieve the French garrison at Badajoz, which the Allies were besieging. The battle ended indecisively, but the French withdrew and failed to achieve their immediate objective.

The fighting was exceptionally costly. Allied losses were about 5,900, while French losses are commonly estimated at roughly 5,900 to 7,900, depending on the source and the treatment of missing or captured soldiers. Relative to the armies’ size, the casualties were extraordinary.

Albuera is sometimes confused with Badajoz, the nearby fortress that was the strategic focus of the campaign. Badajoz was captured in 1812 after a separate and famously devastating assault.