The Battle of Tannenberg, also known as the Second Battle of Tannenberg, was fought between Russia and Germany between 26 and 30 August 1914, the first month of World War I. The battle resulted in the encirclement and the almost complete destruction of the Russian 2nd Army by the German 8th Army and the suicide of its commanding general, Alexander Samsonov. A series of follow-up battles led to the ousting of the Russian 1st Army from East Prussia.