BERTHIER, PIERRE ALEXANDRE, prince of Neu chatel (1753-1815), marshal of France and chief of the staff under Napoleon I., was born at Versailles on Feb. 20, 1753. During the Revolution, as chief of staff of the Versailles national guard, he protected the aunts of Louis XVI. from popular violence, and aided their escape (179r). In the war of 1792 he was chief of staff to Marshal Liickner, and fought in the Argonne campaign of Dumouriez and Kellermann. He served in the Vendean War of and was in the next year made a gen eral of division and chief of staff (major-general) to the army of Italy, which Bonaparte had recently been appointed to com mand. His power of work, accuracy and quick comprehension, combined with his long and varied experience and his complete mastery of detail, made him the ideal chief of staff to a great soldier ; and in this capacity he was Napoleon's most valued assistant for the rest of his career. He accompanied Napoleon throughout the brilliant campaign of 1796, and was left in charge of the army after the peace of Campo Forinio. In this post he organized the Roman republic (1798), after which he joined his chief in Egypt, serving there until Napoleon's return. He assisted in the coup d'etat of 18th Brumaire, afterwards becoming minister of war for a time. In the campaign of Marengo he was the nominal head of the Army of Reserve, but the first consul accompanied the army and Berthier acted in reality, as always, as chief of staff to Napoleon. At the close of the campaign he was employed in civil and diplomatic business. When Napoleon became emperor, Berthier was at once made a marshal of the empire. He took part in the campaigns of Austerlitz, Jena and Friedland, and was created duke of Valengin in 18o6, sovereign prince of Neuchatel in the same year and vice-constable of the empire in 1807. In 18o8 he served in the Peninsular War, and in 1809 in the Austrian War, after which he was given the title of prince of Wagram. Berthier married a niece of the king of Bavaria. He was with Napoleon in Russia in 1812, Germany in 1813, and France in 1814, fulfilling, till the fall of the empire, the functions of "major-general" of the Grande Armee. He abandoned Napoleon to make his peace with Louis XVIII. in 1814, and accompanied the king in his solemn entry into Paris. During Napoleon's captivity in Elba, Berthier, whom he informed of his projects, was much perplexed as to his future course, and, being unwilling to commit himself, fell under the suspicion both of his old leader and of Louis XVIII. On Napoleon's return he withdrew to Bamberg, where he died on June 1, 1815. According to some accounts he was assassinated by members of a secret society; others say that, maddened by the sight of Russian troops marching to invade France, he threw himself from his window and was killed. Berthier was not a great commander; but his title to fame is that he understood and carried out his master's directions to the minutest detail. His Memoires were posthumously published (1827).
See M. Strich, Marschall Alexander Berthier and sein Ende (19o8) .