August Gneisenau , count, a Prussian general, born at Schilda, Oct. 28, 1760, died in Posen, Aug. 24, 1831. He served in the Austrian army, and in that of the margrave of Anspach-Baireuth, with whose troops he served in America under the English, shortly before the close of the revolutionary war. He became captain in the Prussian army in 1789, and after the battle of Jena was appointed commander of the fortress of Colberg (1807), and held the place till the peace of Tilsit. The resentment of Napoleon caused his dismissal (1809), but he was sent on secret missions to various courts. Afterward he was attached to Blucher's army as quartermaster general, and as chief of the staff. (See Butcher.) He took a leading part in the Silesian campaign of 1813, and after the battle of Leipsic was made lieutenant general. He rendered important services during the campaign of 1814 in France, and is said to have advised the march to Paris. After the peace he was made count and general, and received a large estate. After the return of Napoleon from Elba he again served with Blucher, and effected a skilful retreat from Ligny (June 16), enabling the Prussians to reappear at Waterloo (on the 18th), and to decide the fate of the campaign.

He now took part in the negotiations for peace, was made commander of the Rhenish corps, and accompanied Blucher to England. Disappointed in his expectation of constitutional liberty, he tendered his resignation. In 1818 he was appointed governor of Berlin, and in 1825 field marshal; and in 1831, during the Polish insurrection, he commanded the army of observation on the Polish borders, soon after which he died of cholera.