The Battle of Tannenburg was Russia’s worst defeat in World War One. In fact, the Russian army never fully recovered from the battle at Tannenburg and the contribution of Russia’s disillusioned army to the February/March Russian Revolution has been well chronicled. At the start of the war, Alexander Samsonov was appointed commander of the Russian Second Army.
His brief in August 1914 was to invade East Prussia along with General Rennenkampf’s First Army. The start of the campaign went well for Russia. The German commander facing Samsonov, Maximilian Prittwitz, was sacked by Helmuth von Moltke, Germany’s Chief of Staff, for ordering his Eighth Army to retreat as Samsonov’s Second Army advanced. Prittwitz had feared that his army would be encircled after Rennenkampf’s army had defeated the Germans at the Battle of Gumbinnen.
Generals Ludendorff and Hindenburg, replaced Prittwitz. Both men believed that attack was the best form of defence and they ordered that the Eighth Army had to show more aggression in what it did. By August 22nd, they had stabilised the Eastern Front and by August 29th, the Germans surrounded Samsonov’s army. Both Ludendorff and Hindenburg took great credit for what happened at Tannenburg – but the actual details on how to surround Russia’s Second Army came from another German officer – Colonel Maximilian Hoffman.
Samsonov was severely hampered by a lack of communications. He was unaware of what Hoffman was trying to do despite the fact that the Germans were moving around a vast number of men and supplies. He was also unaware that the Russian First Army had halted its advance after its success at Gumbinnen. Samsonov assumed that Rennenkampf was moving as planned through East Prussia.
If the Russian were hampered by poor communications, the Germans greatly benefited from the ease with which they could intercept Russian messages. Two in particular were invaluable to the Germans. One was sent by Rennenkampf to inform Samsonov of his marching plan for the First Army. The message stated clearly that Rennenkampf's army was not marching towards Samsonov's Second Army. Therefore, the Germans could guarantee that Samsonov would get no help from the First Army. The second intercepted message was sent by Samsonov. This stated that he believed that the German army was withdrawing to Tannenburg. It also gave detailed plans for the routes the Russian Second Army was planning to use to advance on the Germans. Therefore, the Germans knew where Samsonov planned to march his army and could plan accordingly.
The attack on Samsonov's Second Army started on August 27th and enjoyed great success. The attack, led by General Francois who commanded the 1 Corps, captured Soldau on the Prussian/Russian border and Samsonov's lines of communication to Russia, already weak, were now severely weakened. Francois then moved the 1 Corps into a position whereby the Russian Second Army could not retreat back to Russia - thus effectively trapping Samsonov. Other German units led by Below and Mackensen were moved to the Tannenburg region and by August 29th, the German army surrounded the Russian Second Army.
One day earlier, on August 28th, Samsonov had realised the severity of his situation and ordered that the Russian Second Army should attempt a breakout near Tannenburg. All efforts ended in costly failure in terms of lost Russian manpower. Many Russian soldiers simply threw away their rifles and surrendered.
Of the 150,000 men in the Russian Second Army, only 10,000 actually managed to escape. There were over 30,000 Russian casualties and more than 95,000 Russian soldiers were taken prisoner. 500 Russian artillery guns were captured. For Russia, the defeat at Tannenburg was a catastrophe. Samsonov committed suicide. Such was the magnitude of the defeat of an ally, the decision was made in London to keep the news away from the British public. Grand Duke Nicholai, commander-in- chief of the Russian Army said to a French military attaché:
"It's an honour to make such a sacrifice for our allies"
In one sense, Nicholai was correct. The Germans had moved one cavalry division and three corps of infantry from the Western Front to the Eastern Front as German military commanders had expected a more substantial battle at Tannenburg. In this sense, the French at the Battle of the Marne had been helped and the German advance on Paris had been halted. However, the loss of morale in the Russian army was immense. That it continued as a military force was simply a comment on the sheer size of the Russian army as opposed to its desire to fight again.