Henry Wellesley, 1st Baron Cowley GCB (20 January 1773 – 27 April 1847) was an Anglo-Irish diplomat and politician. He was the younger brother of the soldier and politician Arthur Wellesley, 1st Duke of Wellington. He is known particularly for his service as British Ambassador to Spain during the Peninsular War where he acted in cooperation with his brother to gain the support of Cortes of Cádiz. His later postings included being Ambassador in Vienna where he dealt with Metternich and British Ambassador to France during the reign of Louis Philippe I.
His career was closely connected with that of his elder brothers Arthur and Richard Wellesley, who served as Foreign Secretary between 1809 and 1812. He became embroiled in a public scandal in 1809 when his wife Charlotte eloped with Henry Paget who as Lord Uxbridge was later to serve as cavalry commander under his brother at the Battle of Waterloo.
Background and education
thumb|[[Portrait of the Marquess Wellesley by Thomas Lawrence. Henry's elder brother Richard Wellesley promoted his diplomatic career in both India and Europe.]]
Wellesley was the fifth and youngest son of Garret Wesley, 1st Earl of Mornington, by Anne Hill-Trevor, eldest daughter of Arthur Hill-Trevor, 1st Viscount Dungannon, both families of Anglo-Irish descent. He was the younger brother of Arthur Wellesley, 1st Duke of Wellington, Richard Wellesley, 1st Marquess Wellesley, and William Wellesley-Pole, 3rd Earl of Mornington. He was educated at Eton and at the court of the Duke of Brunswick. He purchased an ensigncy in the 40th Foot in 1790.
Diplomatic career
Wellesley's diplomatic career began in 1791 when he was appointed attaché to the British embassy at The Hague. The next year, he became Secretary of Legation in Stockholm. In 1791, he exchanged into the 1st Foot Guards and in 1793, he purchased a Lieutenancy. In 1794, while on a trip home from Lisbon with his sister Anne, he was captured by the French, and remained in prison during the height of the terror, escaping only in 1795. Later that year, he sat for the Trim constituency in the Irish House of Commons.
At the 1807 general election he was elected to the House of Commons of the United Kingdom as a Member of Parliament both for the Athlone constituency in Ireland, and for Eye constituency in England.
He chose to sit for Eye, and held the seat until his resignation in 1809