The Battle of Fuentes d'Onoro was fought on May 3rd to 5th 1811 during the Peninsular War, and was one of the most hotly contested battles of the war. Marshal Andre Massena on his way to relieve Almeida, attacked the Duke of Wellington, but failed to capture the position and retired in good order. The Duke of Wellington's doubtful victory then secured the evacuation of Almeida. Research Battle of Fuentes d'Onoro