Robert Thomas Wilson was born in London in 1777. He took up a cornetcy in 15th Light Dragoons in 1793, where he made lieutenant. His service during the Revolutionary Wars saw Wilson distinguish himself a number of times, in particular at the Battle of Villers-en-Cauchies (24 April, 1794) where he was involved in saving Francis II, Holy Roman Emperor, from falling into French hands. Shortly after his return to England and his marriage in March 1798, he served in Ireland, until 1799, at which point he returned to the Netherlands. In 1801, he arrived in Egypt, where he oversaw the correspondence between Lieutenant-General Abercromby and the Turkish general in chief during British opposition to the French invasion led by Bonaparte. After returning to England, he published History of the British expedition to Egypt (1802), notable for its slanderous accusations regarding Bonaparte, including the suggestions that the French general poisoned the plague victims in Jaffa, and ordered the massacre of Turkish prisoners. In 1804 he published an appraisal of the British army, in which he criticised military beatings as a punishment, causing more controversy in Britain. He served in South Africa during Britain's capture of the Cape of Good Hope in 1806, and then accompanied General Hutchinson on his diplomatic mission to the Prussian court in Berlin. After Prussia was defeated by Napoleon, Hutchinson was invited to stay on as military advisor to the Russian tsar, and Wilson remained with him. After peace was agreed at Tilsit in 1807, Hutchinson and Wilson proceeded to St Petersburg. Although they were warmly received by Alexander, Russia's peace agreement with France at Tilsit required the latter to declare war on Britain, which he eventually did in November 1807. After this declaration, the British ambassador to the Russian court, Lord Gower, was dismissed and Wilson returned to London, tasked by Gower to deliver the news and outstrip the Russian messenger dispatched by Alexander to announce the transformation in diplomatic relations between the two countries. Wilson would go on to command the Loyal Lusitanian Legion in Portugal in 1808. Fighting on the frontline of the Peninsular campaign, his efforts were rewarded by a knighthood, a promotion to colonel in the British army and the Portuguese order of the Tower and Sword. He continued to write and in 1810 he published his Brief Remarks on the Character and Composition of the Russian Army and a sketch of the Campaigns in Poland in the years 1806 and 1807. In Turkey in 1811, he proceeded on to Russia in 1812 and there remained as adviser as part of Kutusov's General Staff during the Franco-Russian war and the French retreat. Present at the battles of Maloiaroslavets, Viazma, and Krasnyi, he would later write Narrative of Events during the Invasion of Russia by Napoleon Bonaparte and the retreat of the French Army, 1812, which was published in 1860. He continued to serve with the Russian army during 1813 and was placed in command of the Prussian reserve, distinguishing himself at Bautzen and being awarded the order of St George on the battlefield.
Removed owing to political machinations by Castlereagh, then Foreign Minister, Wilson served with the Austrian Army of Italy during the campaign of 1814. Post-Waterloo, in 1816 he was involved - along with John Hely-Hutchinson and Michael Bruce - in the escape attempt made by the Comte de La Valette following a death sentence being passed on the latter by the French Restoration government. Placed on trial at the French Cour d'assises, he was sentenced to three months in prison and was subsequently criticised by the Prince Regent for his role in the affair. Wilson published a large number of pamphlets (many anonymously) criticising the allied nations; A sketch of the Military and Political power of Russia in the year 1817, published in the Quarterly Review, in particular ruffled feathers. A brief episode in South America in 1818, fighting at the side of Simón Bolívar, followed but this was cut short after Wilson fell out with the Venezuelan and returned to London. In 1818 he became MP for Southwark (as a member of the Whigs) and in 1821 he became involved in a menacing stand-off between attendees of Queen Caroline's funeral and soldiers. The episode was exploited by his political opponents and led to his dismissal from the army without compensation. Elected as MP for Southwark, he also fought on the side of the Cortes in Spain in 1823 following the French invasion. Seriously wounded at La Coruña, he fled to Gibraltar before returning to parliament in 1826 (again for Southwark). His opposition to the parliamentary Reform bill (eventually passed in 1832) led to his resignation. After William IV's arrival on throne in 1830, he was reinstated into the army as lieutenant-general, promoted to general in 1841, and was made governor of Gibraltar in 1842. He remained in this post until a few weeks before his death, in London, on 9 May, 1849.