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Arthur Wellesley, the future Duke of Wellington, was the commanding officer of Charles Stewart, 3rd Marquess of Londonderry, during the Peninsular War (1808–1814). Wellesley led the Allied forces against Napoleon's French forces in the Iberian Peninsula, achieving decisive victories at battles such as Talavera, Salamanca, and ultimately, Waterloo. Londonderry served under Wellesley's command throughout the conflict, gaining recognition for his bravery and leadership.