Wellesley entered the army in 1787 and, aided by his brother Richard (later Marquess Wellesley), rose rapidly in rank. He held a command in Flanders (1794–95) and in 1796 went with his regiment to India. After his brother's appointment (1797) as governor-general of India, he received command of a division in the invasion of Mysore and became (1799) governor of Seringapatam. In 1800 he defeated the robber chieftain, Dhundia Wagh, and in 1802 he was made major general. In 1803 he moved against the Marathas, breaking their force of about 40,000 with an army of about 10,000 in a surprise attack. A valuable civil and military adviser to his brother, he returned with him to England in 1805 and was knighted. His election (1806) to Parliament and appointment (1807) as Irish secretary did not prevent him from leading (1807) an expedition against the Danes.
In 1808 he led an expedition to assist Portugal in its revolt against the French. He defeated the French at Roliça and Vimeiro, but was superseded in command. In 1809 he returned to the Iberian Peninsula, where he ultimately assumed command of the British, Portuguese, and Spanish forces in the Peninsular War. Taking advantage of the irregular terrain, Portuguese and Spanish nationalism, and Napoleon's preoccupation with other campaigns and projects, he drove the French beyond the Pyrenees by 1813, though his campaigns were rendered difficult by poor support from the British government. Late in 1813 he invaded S France, and he was at Toulouse when news of Napoleon's abdication (Apr., 1814) arrived.
Returning to England, he received many honors and was created duke of Wellington. He served for a short time as ambassador to Paris, then succeeded Viscount Castlereagh at the peace conference in Vienna; but when Napoleon returned from Elba, he took command of the allied armies. There followed his most famous victory, that in the Waterloo campaign, won in conjunction with the Prussian general, Gebhard Leberecht von Blücher. Wellington, again lavishly honored, took charge of the army of occupation in France, exerting his influence to restrain harsh treatment of the defeated French.
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