Fought On: August 26 - 30, 1914 (World War I)
  • Russia
    • Second Army Corps under Samsonov (actively participated)
    • First Army Corps under Rennenkampf (did not actively participate)
  • Germany
    • Eighth Army Corps (tranferred to command of Hindenburg on August 23, 1914)

Result: Overwhelming German Victory

Occuring in the early days of World War I, the Battle of Tannenberg was fought between August 26th and 30th of 1914. With the onset of the First World War and the rapid German push into France, the Russians were requested to open a second front in Eastern Germany. Thus it was that two Russian armies would move into German East Prussia, with their ultimate goal being the city of Königsberg. Of the two Russian armies, the First army was under the command of General P.K Rennenkampf and the Second was under the command of General A. V. Samsonov. Coming off a victory in the Battle of Gumbinnen on August 20th, where a German counterattack, consisting of eight divisions of the German Eighth army had been repulsed by Rennenkampf’s First army, the Russians looked poised to dominate the conflict in East Prussia. Meanwhile Samsonov’s forces had crossed the border into East Prussia, on August 22nd, where the Russian Second army had defeated the German 10th corps under their commander Schultz. Schultz was now forced to retreat to Tannenberg and the two Russian armies were doing what they were supposed to up until now, showing early promise in their offensive and forcing the German military command to take troops away from the western assault on France.

The German commander of the 8th army, General von Prittwitz, meanwhile approved a plan proposed by a Lieutenant Colonel Hoffman to strike at the left flank of the Samsonov’s army, with the help of three divisions of the German army being moved in, by rail, to assist from Gumbinnen. Prittwitz though, was not sure of his choice and he also campaigned heavily for the tactical withdrawal of German forces from East Prussia. On the 23rd of August, Prittwitz was replaced by General Paul von Hindenburg and his chief of staff, Erich Ludendorff. Ludendorff would immediately also accept Hoffman’s recommendation with only a few slight modifications from the original plan.

Now the German’s received a gift from the two Russian armies, as the beginning of a massive amount of uncoded Russian communications were intercepted and the German forces learned that Rennenkampf was not going to be moving from his position near Gumbinnen. These messages would continue throughout the battles which followed, allowing the German forces to know the full measure of their enemy, a nearly perfect position for the German leaders to be in. Taking a calculated risk, Ludendorff not only used the three divisions he had pulled off of guarding against Rennenkampf, but he also pulled the rest away from Gumbinnen, leaving only a small screening force of calvary, to try to keep Rennenkampf from moving. Seizing the advantage, the German commanders Hindenburg and Ludendorff struck at the isolated army of Samsonov, whose advanced stretched across nearly 60 miles.

Though the first stages of the invasion of East Prussia had gone well for the Russian forces, the two generals, who held each other in strong disregard, failed to maintain the communication between the two Russian armies. Also, the Russian assault required strong lines of communication, supply and good mobility, qualities which the Russian army lacked in drastic amounts. Initially, the Russian plan had been for Rennenkampf’s First army to attack the German forces from the east while Samsonov’s Second army would attack from the south, forcing the German forces to either split their troops or be caught in a hammer of more than 2 to 1 Russian superiority.

The command was set, with the German 17th corps, under Mackensen, along with the 1st Reserve corps, under Below, hitting the Russian right flank, the 1st corps under Francois hitting the left flank and the center being assigned to Scholtz’ 20th corps. Though Samsonov attacked twice, near the town of Uzdowo (Usdau), his forces were finally forced into a retreat towards Neidenburg, by the German artillery. Though two of the Second army’s divisions were able to escape the tightening German noose, due to a counter-attack by Russian forces out of Soldau, the remaining three divisions were eventually surrounded and the Second army disintegrated. All told, Samsonov lost more than half of his army, including 92,000 prisoners and 30,000 dead to the German’s, no more than, 15,000 casualties. Sometime during August 29th, rather than report his failure, Samsonov is believed to have committed suicide.

The German forces then turned on Rennenkampf’s army, which had not moved at all during the German slaughter of the Second army and thus fully justified Ludendorff’s calculated risk. Fresh with additional reinforcements, the Germans struck at the Russian First army, utterly devastating it at the First Battle of the Masurian Lakes, in the first half of September. All told the Russians lost almost 250,000 men (more than an entire army corps) and almost all of the equipment for both armies, also would never again gain the offensive on the German front for the rest of World War I. The campaign in East Prussia did have one benefit, though not for the Russians, the battles there forced the German high command to focus additional forces on the east, thus making possible the French counter-attack at the Marne and giving the western forces just the breathing room they needed.

This battle should not to be confused with the Battle of Grunwald in 1410, which is oft times also called the Battle of Tannenberg. For, to the victor goes the naming rights.

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