The military commander known for leading forces against Napoleon was the Duke of Wellington, Arthur Wellesley. Wellington played a crucial role in the Napoleonic Wars, particularly at the Battle of Waterloo in 1815, where he commanded the Anglo-allied army that defeated Napoleon. His strategic acumen and leadership were instrumental in the coalition efforts against the French emperor. The victory at Waterloo marked the end of the Napoleonic era and established Wellington as a national hero in Britain, significantly shaping European political dynamics in the aftermath of the conflict.