Battle of Tannenberg

Battle of Tannenberg
Overview
Date	August 26-30, 1914
Location	Near Allenstein and Neidenburg, East Prussia (modern-day Olsztyn and Nidzica, Poland)
Combatants
Germany	Russian Empire
Commanders
Paul von Hindenburg Erich Ludendorff Hermann von François Max Hoffmann	Alexander Samsonov Paul von Rennenkampf
Strength
German Eighth Army (150,000)	Russian Second Army (180,000)
Casualties
12-14,000 killed or wounded	92,000 captured, 78,000 killed or wounded

The Battle of Tannenberg was the climax to the opening clash between Imperial Germany and the Russian Empire following the outbreak of World War I. It was fought between August 26-30, 1914, chiefly around the East Prussian city of Allenstein, and resulted in a crushing victory for the German forces under Field Marshal Paul von Hindenburg and his chief of staff, Erich Ludendorff, with the Russian Second Army almost completely destroyed and its commander, Alexander Samsonov, committing suicide. From a military as well as a political perspective, Tannenberg was among the most important military contests of the war for Germany, as it not only repulsed a Russian invasion of eastern Germany and the threat of a quick defeat, but also elevated Hindenburg and Ludendorff to the status of national heroes. The aura created by their victory would become the basis of their rise to near-dictatorial power in Germany toward the end of the war.

Background

Following the outbreak of war in early August 1914, the German high command, in accordance with the Schlieffen Plan, shifted the vast majority of its troops to the Western Front for a preemptive attack against France. The plan reasoned that Russia, though it had a much larger military, would take considerable time to fully mobilize on account of its great size and primitive infrastructure; therefore the Germans could leave a minimal number of troops on their eastern frontier while achieving a quick victory against the Western Allies, after which the entirety of their forces could be thrown against the Russians. At the outset, then, the border with Russia was defended by a single army stationed in East Prussia, the Eighth, commanded by General Maximilian von Prittwitz und Gaffron. Deployed east of the Vistula River, it had a strength of about 173,000 men.

However, the Russian high command, in order to uphold its alliance with the French, determined to compensate for its weaknesses by mobilizing its available armies at once and sending them forward, while leaving the rest to arm and assemble later. These were the First Army under General Pavel Karlovitch Rennenkampf, stationed in Lithuania and northeastern Poland, and the Second Army under General Alexander Vasilevich Samsonov, massed further south around Warsaw. These two armies, with a combined strength of around 450,000 men, were directed to advance west and north respectively upon East Prussia, converging around the city of Allenstein (modern Olsztyn, Poland). While Rennenkampf marched through the Insterburg Gap between Königsberg and the Masurian Lakes to engage Prittwitz's front, Samsonov would bypass the Lakes from the south to turn the Germans' right flank.

Though the Russians held a significant numerical advantage over the defenders, as well as the strategic value of an unexpectedly early offensive, they were beset by a number of disadvantages: many of the troops were poorly armed and equipped, owing to the incomplete mobilization; their artillery component was notably weak compared to the Germans'; though both Rennenkampf and Samsonov were capable officers, the latter was relatively new to his command, having previously served in the Far East and in Turkestan; and the Russians' supply lines would be inadequate once they advanced into Germany (Russia's use of a different rail gauge meant its cars could not run on German tracks). Another drawback that would prove significant was that the Russian army had neither a proper coding system in use, nor sufficient telephone or telegraph cable to run secure communication lines from front-line units to headquarters. As a result, once on German soil many military communications would be sent as "clear" (that is, uncoded) wireless messages, which the Germans frequently intercepted.

Prelude

Though Russian units had made forays across the frontier as early as August 12, the main offensive opened on the 17th, when Rennenkampf's First Army crossed the border in force, headed for the Insterburg Gap; Samsonov's Second Army invaded from the south two days later. On the first day of his advance, Rennenkampf met resistance at the town of Stallupönen from a portion of the German I Corps under Lieutenant General Hermann von François, which drove the Russian 27th Division back in a chaotic retreat and took some 3,000 prisoners. This attack had been unauthorized by Prittwitz, who ordered François to fall back toward the Eighth Army's main line on the Angerapp River that night; the promising results of Stallupönen, though, and the sluggish pace of the Russian advance, convinced the general to launch a more general counterattack, in hopes of defeating Rennenkampf before Samsonov brought his forces to bear.

Prittwitz attacked near the town of Gumbinnen on the morning of August 20, with generally negative results. The I Corps under François enjoyed some success, assaulting the right flank of the Russian XX Corps and driving it from the field after its artillery ammunition ran out. However, the other units--the XVII Corps under Lieutenant General August von Mackensen and the I Reserve Corps under General Otto von Below--had had to hastily advance from the Angerapp and thus were not in a position to do more than launch frontal attacks, which the Russians easily repulsed. Under heavy bombardment, Mackensen's and Below's troops broke and fled the field, and by nightfall Prittwitz had ordered the whole army to pull back. Though Rennenkampf declined to pursue the retreating troops, due to concern about the state of his supply lines, reports had by now arrived of Samsonov's offensive from the south; in response, Prittwitz gave orders for Eighth Army to retreat all the way to the Vistula, which would mean abandoning most of East Prussia. That same night, he telephoned Field Marshal Helmuth von Moltke, overall commander of the German armies, to explain his intentions.

The planned retreat of the Eighth Army produced consternation at Moltke's headquarters, which had been under the impression that it was holding its own against the invasion. However, Prittwitz's orders were altered again the following day, August 21, when his staff convinced him a southward shift was necessary to block Samsonov's advance before the withdrawal to the Vistula could begin. Most units were accordingly reoriented away from the front of the First Army (which remained quiet), but Prittwitz rejected proposals that he counterattack Samsonov in turn, and in follow-up conversations with headquarters (Oberste Heeresleitung, or OHL), made clear his determination to take up a defensive stance behind the Vistula, and suggested reinforcements from the Western Front would be necessary even to hold that line.

Appointment of Hindenburg

Although the Schlieffen Plan had accepted the likelihood of a brief occupation of Germany's eastern fringe, until all of its military power could be thrown against the Russian foe, the actual prospect of abandoning East Prussia was not acceptable to the political and military leadership, and pressure was rapidly building for a complete change in policy, and if necessary, commanders. Moltke had for some time wanted to replace Prittwitz, whom he considered too old and temperamentally unfit for his job, and the general's vacillating conduct on August 20-21 was not received well at OHL. The conversation of the 21st, in which Prittwitz expressed his decision to give up most of East Prussia and even implied he would retreat from the Vistula without reinforcements, probably sealed his fate. That evening, Moltke decided to relieve both Prittwitz and his chief of staff, Major General Alfred von Waldersee, of their commands.

Generals Paul von Hindenburg (left) and Erich Ludendorff

To lead the Eighth Army, Moltke and OHL selected a retired Prussian general, Paul von Beneckendorff und Hindenburg, who had served on the Army General Staff and later been a corps commander; though 67 years old and not especially brilliant or vigorous, he was regarded as solid and dependable, which was what the Eastern Front needed at the moment. Hindenburg received the request to take command at his home in Hanover the following afternoon and agreed at once. At the same time, the OHL sought a new chief of staff (an especially important position in the German army, to the extent that such a person was often effectively a co-commander). It chose Major General Erich Ludendorff, who had distinguished himself earlier that month in the siege of Liège on the Western Front as a man with a penchant for quick and decisive action. The hope was that he would thus be an ideal complement to Hindenburg. Ludendorff was summoned from his position on the 22nd and dispatched east by train that same evening, joining Hindenburg (the two had never previously met) in Hanover the following morning and continuing on to Eighth Army headquarters in Marienburg, arriving on the afternoon of the 23rd and formally taking over from Prittwitz and Waldersee.

Opening Phase: August 23-26

Despite the Russians' early success, the crippling problems of communication and supply continued to worry their high command. In particular, communications between Samsonov and General Yakov Zhilinskiy, who had overall responsibility for the front, were patchy and delayed, and out of concern this would cause Samsonov to hesitate, Zhilinskiy repeatedly sent messages (intercepted by German radio) urging haste on the part of Second Army. Samsonov was in fact marching north into East Prussia with all possible speed, having crossed the border on the 19th and pushing back the heavily outnumbered XX Corps over the next few days. However, his troops had by now outrun their supply lines and were growing exhausted in the summer heat, and there was a gap of over sixty miles between them and Rennenkampf's First Army.

Already on August 21, the Eighth Army deputy chief of operations, Colonel Max Hoffmann, had issued orders for most of the other units to shift southward and support XX Corps, gambling that Rennenkampf would remain inactive. Upon receiving his new assignment, Ludendorff, with Hindenburg's approval, confirmed these orders, reasoning that with Samsonov still advancing, and the two armies geographically separated, the only real option was to mass all possible force against them one at a time, with the prospect of defeating them in detail.

By August 23, the XX Corps had formed a defensive line between the villages of Orlau and Frankenau, which was assaulted the following morning by Samsonov's XV Corps under General Nikolai Martos. After heavy losses on both sides, the German commander, Lieutenant General Friedrich von Scholtz, pulled back another ten miles, forming a new line based around the village of Tannenberg. Owing to the poor communications, Samsonov believed that Rennenkampf was still keeping the bulk of the Eighth Army occupied further northeast, and therefore ordered a continued advance by all four of his corps the following day--this message too was intercepted and reported to the German commanders. In fact, Hindenburg and Ludendorff, who had come to Tannenberg that same day to confer with Scholtz, regarded it as a confirmation of their initial decision and summoned Mackensen's and Below's corps to march south at once to reinforce the XX Corps. Simultaneously, François' I Corps, which had been moving from Gumbinnen to the Tannenberg sector via train the past several days, was ordered to attack the Russian left flank at Usdau the next morning, the 25th; though François protested--in vain--that as his ammunition had not yet arrived, his troops would have to rely on the bayonet. Mackensen, supported by Below, would meanwhile assail the Russian right, while Scholtz engaged their center.

As the battle was being planned, OHL telephoned Eighth Army headquarters to inform them it was sending three corps and a cavalry division from the Western Front. Ludendorff, who from his time on the General Staff knew the heavy emphasis the Schlieffen Plan placed on an overwhelming flanking assault against the French, protested that the troops were not "positively" needed and could not arrive in time to make a difference; but OHL, under stiff political pressure to spare East Prussia from Russian occupation, insisted (though only two corps were actually sent).

Main Battle: August 26-30

Though ordered to begin the attack, François delayed advancing his troops for some time until their ammunition could arrive, despite angry demands by Ludendorff. When the battle ultimately began on the 26th, it was sparked instead by Mackensen, whose XVII Corps moved forward against the Russian VI Corps around Bischofsburg, near the Masurian Lakes. It struck an isolated divison, which lost 5,000 men and sixteen guns before day's end; a second division arrived to reinforce them, but by then Below's corps had also arrived, and through the rest of the day and into the night the VI Corps was steadily pushed back. Further west, where Scholtz was attacking the Russian center, the contest was initially more even. Over the past two days, Samsonov had received enough information to convince him most of Eighth Army was facing him and about to go over to the offensive, and had attempted to reinforce Martos with the XIII Corps of General Nikolai Klyuev and part of the XXIII Corps of General Kyprian Kandratovich. Thus strengthened, Martos' line did not break, but both his left flank (near Osterode) and his right flank (near Allenstein), in the latter case due to Mackensen and Below's defeat of VI Corps, were in danger of being turned. Though aware of the danger, Samsonov decided not to retreat but to hold his position the next day, in the belief that Rennenkampf must by now be threatening the German rear--in reality, Rennenkampf was slowly moving northwest towards Königsberg, and posed no immediate threat to Eighth Army.

German soldiers at the Battle of Tannenberg

During that same day, German headquarters was in a state of nervous tension, owing to François' failure to advance, and also to mistaken reports from aerial reconnaissance that Rennenkampf's First Army might be moving in their direction. Ludendorff experienced a brief panic, and seems to have considered breaking off the battle; however, during a private conversation with Hindenburg, the latter apparently stiffened his resolve, as orders were shortly sent to continue the attack.

By nightfall, François' ammunition had finally arrived, and he was ready to begin his attack. In the early morning hours of the 27th, he launched a massive artillery bombardment that broke the Russian I Corps, holding the far left of Samsonov's line at Usdau; by midday, it had abandoned its positions, and François was able to take the field without any serious action by his infantry. Though Samsonov's left later rallied, it was clear his army was now in serious danger of a double envelopment. By day's end, even Zhilinskiy had recognized this fact, and sent Rennenkampf new orders to move to Second Army's support; given the great distance between them, though, it was impossible for him to render Samsonov any immediate help.

The following day, the 28th, saw intense and often confused fighting all along the line. François continued to press around the Russian left in hopes of gaining Samsonov's rear and cutting off his retreat; while Scholtz's XX Corps was, in the opinion of Ludendorff, almost "exhausted" by the past several days of continuous battle, Mackensen, after a slow start, again engaged with the isolated VI Corps and drove it back further, while Below reached Allenstein and threatened to separate the Russian center and right entirely. Samsonov himself, demoralized by the collapse of I Corps on his left, which he had counted on to stabilize the rest of his army, traveled to the front and attempted to personally direct the fighting in Martos' sector; by nightfall, though, he had concluded the situation was irretrievable, and issued orders for a general retreat.

Though much of the broken I and VI Corps, being already partially driven from the field, would in fact be able to escape on the 29th, there was little chance of retreat for the XIII and XV Corps in the center. Below had succeeded in breaking through at Allenstein, and with Mackensen was able to link up with François near Neidenburg, effectively surrounding those two corps. Martos' and Klyuev's men desperately floundered through the forests and swamps inside the pocket, looking for an open path to escape, but there were few passable roads, and on all of these the Germans had already posted machine guns to mow down anyone in sight. Moreover, the troops had run completely out of food, in some cases for several days, and were growing physically incapable of further resistance. Through the day and night more and more of them were rounded up; Martos and Klyuev were themselves captured, and by the following morning, except for a final attack by a regrouped portion of the Russian I Corps, all fighting was at an end.

Samsonov himself had also been trapped in the surrounded pocket. Rather than face the shame either of being taken prisoner or of telling Czar Nicholas II that he had lost his army, the general walked into the forest about 1:00 a.m. on the 30th and shot himself. His body was later discovered by the Germans and returned to Russia.

Aftermath

Tannenberg is often considered one of the most complete tactical victories scored by either side in the First World War. The Russian Second Army was virtually destroyed as a result of the battle: out of an initial strength of about 180,000 men, about 92,000 had been captured and anywhere between 30,000 and 78,000 killed or wounded. Some 350 pieces of artillery were also taken by the Germans. Losses were proportionally highest in the XIII and XV Corps, from which together fewer than 2200 men escaped, including a single officer of the entire XV Corps. By comparison, out of about 150,000 Germans engaged at Tannenberg, only about 12-14,000 became casualties.

Of the many factors that contributed to the German success, the most important are regarded as the appointment of Hindenburg and Ludendorff; the Russians' many supply problems brought on by their rushed mobilization, as compared to the Germans' ability to quickly move troops from one point to another via a superior rail system; and not least the Russian reliance on uncoded wireless communications that the Germans could intercept, thus discovering their intended movements. Colonel Hoffmann of the Eighth Army staff later said of the campaign, "We had an ally--the enemy. We knew all the enemy's plans."

After the battle, either Ludendorff or Hoffmann decided to name it "Tannenberg." Though the village itself had served as Scholtz's headquarters for part of the action, the battle had unfolded along a front of more than 50 miles, and some of its most critical phases had occurred around other, larger towns, such as Allenstein and Neidenburg. However, the name Tannenberg carried with it great historical weight, having been the site of a battle in 1410 in which the German Teutonic Knights had been defeated by Poland-Lithuania. Thus, it was received by the Germans as not only a victory in the current conflict, but the avenging of that earlier event. (Hindenburg personally, claiming descent from the Teutonic Knights, strongly supported the proposed name.)

The results of Tannenberg were neither as drastic nor as immediate as sometimes claimed. It did not end the Russian presence on German soil, as Rennenkampf's First Army still occupied part of East Prussia; that would continue until German victory at the First Battle of the Masurian Lakes the following month. Though Russian morale was shaken by the defeat, this was tempered somewhat by their own crushing triumph over the armies of Austria-Hungary in Galicia during the same period. Moreover, though Tannenberg had ended the prospect of a more thorough invasion of eastern Germany, the Russians had achieved their greater strategic purpose: by rapidly mobilizing and provoking fear among the German political and military leadership, they had led Moltke and the OHL to detach two corps from the critical Western Front to support the Eighth Army, weakening the armies sweeping through Belgium and into France when overwhelming strength was a necessity. After the narrow Franco-British victory at the First Battle of the Marne in September, a French officer stated, "Let us render to our Allies {i.e. Russia} the homage that is their due, for one of the elements of our victory was their debacle."

After Tannenberg, an official inquiry by the Russians blamed Zhilinskiy for poorly coordinating the operations of the two armies; he was relieved of command and sent to France as a military liaison. Rennenkampf was exonerated, but then dismissed after his defeat at the Masurian Lakes and forced into retirement in 1915. By contrast, Hindenburg and (to a lesser extent) Ludendorff were hailed as heroes in Germany, with medallions, postcards, and other media featuring Hindenburg's image quickly manufactured and distributed across the country. The aura created by Tannenberg (and by their subsequent successes on the Eastern Front) would lead to the two men being given supreme military authority in 1916 and becoming effective co-dictators thereafter, wielding more real power inside Germany than either the Kaiser or the Reichstag. In this way, the outcome of Tannenberg strongly influenced the course of events within wartime Germany.