French general, known for the part he played in the War of American Independence and the revolutionary wars. Until 1788, when he succeeded to the duchy of Biron on the death of his uncle,—Louis Antoine de Gontaut, duc de Biron (1700–1788)—he bore the title of duc de Lauzun, which had passed, on the death of Antoine Nompas de Caumont, duc de Lauzun (1632/3–1723), to his niece, the wife of Charles Armand de Gontaut, duc de Biron (1663–1756). After for a while wasting his fortune in dissipation in various parts of Europe, he attracted attention by an essay on the military defences of Great Britain and her colonies (État de défense d’Angleterre et de toutes ses possessions dans les quatres parties du monde). This led to his appointment to a command against the English in 1779, in which he gained several successes. In the following year he took a conspicuous part in the War of American Independence, and on his return to France was made maréchal de camp. In 1789 he was returned as deputy to the states-general by the noblesse of Quercy, and attached himself to the revolutionary cause. In 1791 he was sent by the Constituent Assembly to receive the oath of the army of Flanders, and subsequently was appointed to its command. In July 1792 he was nominated commander of the army of the Rhine, with the duty of watching the movements of the Austrians. In May 1793 he was transferred to the command of the army of La Rochelle, operating against the insurgents of La Vendée. He gained several successes, among them the capture of Saumur and the victory of Parthenay; but the insubordination of his troops and the intrigues of revolutionary agents made his position intolerable and he sent in his resignation. He was thereupon accused by the notorious Carrier of incivisme and undue leniency to the insurgents, deprived of his command (July), imprisoned in the Abbaye and condemned to death by the Revolutionary Tribunal. He was guillotined on the 31st of December 1793. Some Mémoires, which come down to 1783, were published under his name in 1822 (new ed., 1858), and in 1865 letters said to have been written by him in 1789 to friends in the country, describing the states-general.
