Battle of Tannenberg - Conflict & Dates:
The Battle of Tannenberg was fought August 23-31, 1914, during World War I (1914-1918).
Armies & Commanders
Battle of Tannenberg - Background:
With the outbreak of World War I, Germany began implementation of the Schlieffen Plan. This called for the bulk of their forces to assemble in the west while only a small holding force remained in the east. The goal of the plan was to quickly defeat France before the Russians could fully mobilize their forces. With France defeated, Germany would be free to focus their attention to the east. As dictated by the plan, only General Maximilian von Prittwitz's Eighth Army was allocated for the defense of East Prussia as it was expected that it would take the Russians several weeks to transport their men to the front (Map).
While this was largely true, two-fifths of Russia's peacetime army was located around Warsaw in Russian Poland, making it immediately available for action. While the bulk of this strength was to be directed south against Austria-Hungary, who were only fighting a largely one-front war, the First and Second Armies were deployed north to invade East Prussia. Crossing the frontier on August 15, General Paul von Rennenkampf's First Army moved west with the goal of taking Konigsberg and driving into Germany. To the south, General Alexander Samsonov's Second Army trailed behind, not reaching the border until August 20.
This separation was enhanced by a personal dislike between the two commanders as well as a geographic barrier consisting of a chain of lakes which forced the armies to operate independently. After Russian victories at Stallupönen and Gumbinnen, a panicked Prittwitz ordered the abandonment of East Prussia and a retreat to the Vistula River (Map). Stunned by this, the Chief of the German General Staff, Helmuth von Moltke sacked the Eighth Army commander and dispatched General Paul von Hindenburg to take command. To aid Hindenburg, the gifted General Erich Ludendorff was assigned as chief of staff.
Just prior to the change in command, Prittwitz's deputy chief of operations, Colonel Max Hoffmann, proposed a bold plan to crush Samsonov's Second Army. Already aware that the deep animosity between the two Russian commanders would preclude any cooperation, his planning was further aided by the fact that the Russians were transmitting their marching orders in the clear. With this information in hand, he proposed shifting the German I Corps south by train to the far left of Samsonov's line, while the XVII Corps and I Reserve Corps were moved to oppose the Russian right.
This plan was risky as any turn south by Rennenkampf's First Army would endanger the German left. In addition, it required the southern portion of the Königsberg defenses to be left unmanned. The 1st Cavalry Division was deployed to screen to the east and south of Königsberg. Arriving on August 23, Hindenburg and Ludendorff reviewed and immediately implemented Hoffmann's plan. As movements began, the German XX Corps continued to oppose Second Army. Pushing forward on August 24, Samsonov believed his flanks to be unopposed and ordered a drive northwest towards the Vistula while VI Corps moved north to Seeburg.
The Battle of Tannenberg:
Concerned that the Russian VI Corps was making a flanking march, Hindenburg ordered General Hermann von François' I Corps to begin their attack on August 25. This was resisted by François as his artillery had not arrived. Eager to begin, Ludendorff and Hoffmann visited him to press the order. Returning from the meeting, they learned through radio intercepts that Rennenkampf planned to continue moving due west while Samsonov pressed XX Corps near Tannenberg. In the wake of this information, François was able to delay until the 27th, while XVII Corps was ordered to attack the Russian right as soon as possible (Map).
Due to I Corps' delays, it was XVII Corps which opened the main battle on August 26. Attacking the Russian right, they drove back elements of the VI Corps near Seeburg and Bischofstein. To the south, the German XX Corps was able to hold around Tannenberg, while the Russian XIII Corps drove unopposed on Allenstein. Despite this success, by the end of the day the Russians were jeopardy as XVII Corps had begun to turn their right flank. The next day, the German I Corps began their assault around Usdau. Using his artillery to advantage, François broke through the Russian I Corps and began advancing.
In an effort to save his offensive, Samsonov withdrew XIII Corps from Allenstein and re-directed them against the German line at Tannenberg. This led to the majority of his army being concentrated east of Tannenberg. Through the day on the 28th, German forces continued to drive back the Russian flanks and the true danger the situation began to dawn on Samsonov. Requesting Rennenkampf to divert to the southwest to provide aid, he ordered Second Army to begin falling back to the southwest to regroup (Map).
By the time these orders were issued, it was too late as François' I Corps had advanced past the remnants of the Russian left flank and assumed a blocking position to the southwest between Niedenburg and Willenburg. He was soon joined by XVII Corps which, having defeated the Russian right, advanced southwest. Retreating southeast on August 29th, the Russians encountered these German forces and realized they were surrounded. The Second Army soon formed a pocket around Frogenau and was subjected to relentless artillery bombardment by the Germans. Though Rennenkampf made attempts to reach the beleaguered Second Army, his advance was badly delayed by the German cavalry operating on his front. Second Army continued to fight for another two days until the bulk of its forces surrendered.
Aftermath of Tannenberg
The defeat at Tannenberg cost the Russians 92,000 captured, as well as another 30,000-50,000 killed and wounded. German casualties totaled around 12,000-20,000. Dubbing the engagement the Battle of Tannenberg, in vindication of the Teutonic Knight's 1410 defeat on the same ground by a Polish and Lithuanian army, Hindenburg succeeded in ending the Russian threat to East Prussia and Silesia. Following Tannenberg, Rennenkampf began a fighting retreat which culminated in a German victory at the First Battle of the Masurian Lakes in mid-September. Having escaped the encirclement, but unable to face Tsar Nicholas II after the defeat, Samsonov committed suicide. In a conflict best remembered for trench warfare, Tannenberg was one of the few great battles of maneuver.