Louis Alexandre Berthier, prince and duke of Neufchatel and Valengin, and prince of Wagram, a French soldier, born in Versailles, Nov. 20, 1753, died in Bamberg, June 1, 1815. His father was chief of the corps of topographical engineers. After studying in the topographical bureau he became lieutenant in the general staff and afterward captain of dragoons, and served in the American war under Lafayette. As general of the national guard of Versailles he rendered good service to the royal family in October, 1789. Afterward he was chief of the general staff, under Lafayette, Luck-ner, and Custine. He participated in the unsuccessful defence of Saumur in June, 1793. After the 9th Thermidor he was appointed chief of the general staff of Kellermann, and by causing the French army to take up the lines of Bor-ghetti contributed to arrest the advance of the enemy. He also proved himself a good general of division in the battles of 1796-7 in Italy, and excelled as a staff officer by his grasp of all the details of the service, though he had not the genius required for supreme command.
Despite his remonstrances, Bonaparte placed him in 1798 at the head of the army of occupation in Rome; but he resigned his command to Massena, and went to Milan, where he fell in love with the beautiful Madame Visconti, his eccentric and lasting passion for whom caused him during the expedition to Egypt to be nicknamed the chief of the faction des amoureux, and absorbed the greater part of the vast sums bestowed upon him by his master. After his return from Egypt he seconded Bonaparte on the 18th and 19th Brumaire, and was minister of war till April 2, 1800. He was chief of the general staff at the battle of Marengo, concluded an armistice with Gen. Melas, was employed on several diplomatic missions, and reinstated in the war ministry till the proclamation of the empire. With the title of major general of the grand army, he accompanied the emperor as chief of the general staff during all his subsequent campaigns. On Oct. 17, 1805, he negotiated with Mack the terms of the capitulation of Ulna. After the Prussian campaign of 1806 he was made sovereign prince of Neufchatel and Valengin. In 1808 he was ordered to marry the princess Elizabeth Maria of Bavaria-Birkenfeld, the king of Bavaria's niece, and was made marshal and vice constable of Fiance. In 1809 Napoleon placed him as general-in-chief at the head of the grand army destined to operate from Bavaria against Austria. He won no glory in this capacity, but again distinguished himself in the battle of Wagram, which procured him one of his princely titles.
He failed, however, com-pletely during the Russian campaign. After the senate had decreed the deposition of the emperor, Berthier was one of the first to pay court to Louis Will., who made him a peer and captain of the royal guard. During the hundred days he wished to remain neutral, concealed from the king a letter he had received from Napoleon announcing his purpose to leave Elba, and retired to Bamberg, where, according to some, he was thrown from a window of his father-in-law's palace by six men in masks, supposed to have been agents of a secret society; but, according to a more probable account, he threw himself from the balcony at the sight of Russian troops marching toward France. He wrote Relation des campagnes du general Bonaparte en Egypte et en Syrie (Paris, 1800), and Relation de la hataille de Marengo (1806); and his memoirs were published in 1826. - His only son, Napoleon Louis Joseph Alexandre Charles, duke and prince of Wagram, born in Paris, Sept. 11, 1810, became a senator in 1852, and has greatly improved agriculture in his vast domain of Gros-bois. He married a daughter of Count Clary and cousin of the dowager queen of Sweden, and is the father-in-law of Prince Joachim Murat.