Charles Stuart, 1st Baron Stuart de Rothesay (2 January 1779 – 6 November 1845), known as Sir Charles Stuart between 1812 and 1828, was a British diplomat. He was twice Ambassador to France and also served as Ambassador to Russia between 1841 and 1844. Background and education Stuart was the son of the Lieutenant-General The Honourable Sir Charles Crichton-Stuart, younger son of Prime-Minister John Stuart, 3rd Earl of Bute. His mother was Louisa Bertie, daughter of Lord Vere Bertie, younger son of Robert Bertie, 1st Duke of Ancaster and Kesteven. He was educated at Eton and Christ Church, Oxford. Diplomatic career Stuart joined the Diplomatic Service in 1801, and was immediately appointed as Secretary of Legation in Vienna, Holy Roman Empire, a post he held until 1804. He was then sent to Petersburg and this was followed by an assignment in French occupied Spain in 1808. He served as Envoy Extraordinary and Minister Plenipotentiary to Portugal and Brazil between 1810 and 1814. He was appointed a Knight of the Most Honourable Order of the Bath (KB) in 1812 and sworn of the Privy Council in 1814. Briefly Ambassador to the Netherlands between February and May 1815, it was during his posting as Ambassador in Spain that he became indispensable to the Duke of Wellington. At the Generals' insistence, he was appointed British Ambassador to France. During Napoleon's Hundred Days, he left Paris and was in Brussels at the start of the Waterloo Campaign, where during his stay he attended the Duchess of Richmond's Ball. After the fall of Napoleon, he escorted the exiled French King Louis XVIII back to Paris, and became British Ambassador there until 1824. In 1815 he was made a Knight-Grand-Cross in the civil division of the Most Honourable Order of the Bath (GCB). From 1825 to 1826 he was once more Envoy Extraordinary and Minister Plenipotentiary to Portugal and Brazil. In 1825 the Portuguese King John VI named Stuart his plenipotentiary with powers to negotiate and sign with Brazil a Treaty on the recognition of that country's independence. Invested with those powers, Stuart signed the treaty recognising Brazilian independence on 29 August 1825, and on 15 November of the same year the Portuguese King ratified the treaty. He was then created 1st Count of o Machico by Decree of 22 November 1825 by John VI of Portugal and later 1st Marquess of Angra by Decree of