JOMINI, HENRY, BARON (1779-1869), general in the French and afterwards in the Russian service, and writer on military tactics, was born 6th March 1779 at Payerne in the canton of Vaud, Switzerland, where his father held the dignity of magistrate. At an early period he showed a marked preference for a military life, but at first he was disappointed of his hopes by the dissolution of the Swiss regiments of France at the Revolution. For some years he acted as clerk in a banking house in Paris, until the outbreak of the Swiss revolution, when he returned to his native country, and at the early age of nineteen was appointed chief secretary of war. At the peace of Luneville in 1801 he returned to Paris and introduced himself to Marshal Ney, who made him his aide-de-camp and private secretary. In 1804 he published Traite des grandes operations miliMires, which in 1805 he presented to Napoleon on the field of Austerlitz as the work of a young Swiss officer. A few days afterwards he was named colonel, and appointed first aide-de-camp to Marshal Ney. In 1806 he published a treatise on the probabilities of the war with Prussia, the ability of which so impressed Napoleon that he resolved to attach him to his person. He was present with Napoleon at the battle of Jena, but afterwards joined Ney, and afforded him important assistance in delivering his army from a very perilous situation. After the peace of Tilsit he was made chief of the staff to Ney, and created a baron. In the Spanish campaign of 1808 his skilful advice contributed in no small degree to the victories of Ney, but on account of that general's jealousy he resigned his commission, and he was entering into negotiations with the emperor of Russia, when Napoleon, learning his intention, compelled him to remain in the French service with the rank of brigadier-general. On his refusal to take part in the Russian campaign, Napoleon named him governor of Vilna; but during the retreat from Moscow he at once placed his strategic skill and knowledge of the country at the service of France, and, having after the battle of Liitzen obtained his old office under Marshal Ney, he suggested the happy matmeuvre which led to the victory of Bautzen. Finding, however, that the road to promotion was closed against him, he again offered his services to Russia. They were accepted, and he obtained the rank of lieutenant-general and was named aide-de-camp to the emperor. He gave the important assistance of his counsel to the allied armies during the German campaign, but declined to take part in the passage of the Rhine and the invasion of France in 1814. In 1817 he returned to Paris, where he published Principes de la strategie, 3 vols., 1818; Ilistoire •itigae et militaire des campagnes de la Revolution de 1192 a 1801, 15 vols., 1819-24; Vie politique et militaire do Napoleon, 1827. In 1826 he again entered the service of Russia, and in the Turkish campaign of 1828 his sagacious advice led to the capitulation of Varna. Afterwards he was employed in organizing the military academy at St Petersburg and in superintending the military studies of the czarowitz, for the use of whom he wrote Tableau anal ytigue des principales combinaisons de la guerre, the new and improved edition of which was named Precis de l'crt de la guerre. During the later period of his life Jomini resided at Brussels, but lie afterwards returned to Paris, where he died March 24, 1869. Although Jomini played a secondary and unobtrusive part in the great military events of his time, the military triumphs of France were in no inconsiderable degree due to his masterly counsels ; and doubtless, had circumstances conspired to grant him the opportunity of playing a practical and independent role, he would have achieved for himself a place among the greatest generals of his country. His delineations of the campaigns of Napoleon are the ablest military account of these great wars, and his exposition of the laws of tactics and strategy have achieved for him European fame.

See Ferdinand Leconte, Le General Jonzini, sa vie et scs &pits, 1861 ; and Le General Jomini, by Sainte-Beuve, 1869.