TANNENBERG, BATTLE OF. No portion of the earth's surface has been more fought over than East Prussia. It was in 1410, on the field of Tannenberg, that the Teutonic knights were utterly routed by their enemies the Poles and Lithuanians, and the German victory of 500 years later was in some degree the reversal of this defeat.
The Tannenberg of 1914 was the greatest victory achieved by any of the combatants at the commencement of the World War, and its strategic and moral effect upon the struggle were far reaching. France and Russia had been joined by military con vention since 1892 and their chiefs of staff had made careful ar rangements for concerted action. In case of war with the Central Powers it had been agreed that Germany was the main enemy and that the principal military effort must be made against her.
Owing to the vastness of her territory and to the comparatively undeveloped state of her railways, Russia's rate of concentra tion was considerably slower than that of France, so much so that there was a danger of the latter being crushed before the attack on Germany in the East could begin to exert its effect. Unfortunately, under the pressure of French insistence, the good will and optimism of Russia's military leaders exceeded practical possibilities and the outbreak of war found her military plans in some disorder. All their initial operations in East Prussia were in fact hasty improvisations.
Geographically, East Prussia points forward into the heart of Slavdom and constituted a difficult problem of defence tor uer many. True to her policy of concentration of force at the deci sive point, she had decided to advance against France with her main forces whilst maintaining only a minimum of strength in the East. Not wishing to abandon national territory without a i blow, she had decided to concentrate this minimum strength in East Prussia, despite the dangers involved in such action. Ger many's strength in the East was to consist of i r divisions, six first-line and five second-line, with but a single cavalry division.
Taking the East Prussian front as it appeared to the Russians, we can divide it militarily as follows : (a) Konigsberg Area.—A more or less fortified area extending over the Konigsberg peninsula, of a depth of 19 m. from north to south. In the centre lay the obsolete fortress, strong against anything but heavy artillery. The area could be reinforced by sea through the canal from Pillau. It formed a strong flanking position from which to attack any force to the south.
(b) Insterburg Gap.—A gap of 43 m. of open country, down which ran the main Insterburg-Allenstein railway. The River Angerapp running north and south blocks this gap. It formed an excellent line of defence with the right flank resting against the impassable Lake Mauer.
(c) Masurian Lakes.—A line of continuous lakes from Anger burg to the Russian frontier at Johannisburg, a distance of 5o miles. The narrow gaps between the lakes could be held with few troops, and the whole line presented an almost impregnable front behind which the Germans could operate to either flank.
(d) Johannisburg-Dzialdowo (Soldau) Front.—A distance of 75 m. running east and west. On the Russian side the country had been left a desert as a defence against Germany.
Rennenkampf's army crossed the frontier on Aug. 17 with a strength of 6 divisions and 53 cavalry divisions. On the loth an action was fought with the German VIII. Army at Gumbinnen. Prittwitz, the German commander in the East, had concentrated his main strength to meet Rennenkampf, six divisions and a cav alry division, whilst leaving some two divisions to face Samsonov's army, which was concentrating on the River Rennenkampf had moved off without a great portion of his transport and found himself forced to halt on the loth. Pritt witz advanced to attack him. There were serious miscalculations in the German movements, with the result that the action was indecisive, both sides suffering heavy losses. That evening the news arrived that Samsonov had not only started to advance, but that two of his corps were already close to the frontier and that he had at least five corps with him. The German commander abandoned all hope of defeating Rennenkampf on the 21st and contemplated a withdrawal to the Vistula. On communicating this on the telephone to the supreme command, he and his chief of staff were at once superseded.