Changes

| image      =

| image      =

| conflict    =  

| conflict    =  

| date        =August 26-30, 1914

| date        =August 26–30, 1914

| location    =Near Allenstein and Neidenburg, [[East Prussia]] (modern-day Olsztyn and Nidzica, [[Poland]])

| location    =Near Allenstein and Neidenburg, [[East Prussia]] (modern-day Olsztyn and Nidzica, [[Poland]])

| combatant1  =[[Germany]]

| combatant1  =[[Germany]]

| casualties2 =92,000 captured, 78,000 killed or wounded  

| casualties2 =92,000 captured, 78,000 killed or wounded  

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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.

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==

==Background==

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.

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.<ref>Dennis E. Showalter, ''Tannenberg: Clash of Empires, 1914'' (1991), p. 195-96.</ref>   

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.<ref>Dennis E. Showalter, ''Tannenberg: Clash of Empires, 1914'' (1991), p. 195-96.</ref>   

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.

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==

==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.

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.

[[File:Generalfeldmarschall_von_Hindenburg_und_General_Ludendorff.png|thumb|270px|right|Generals [[Paul von Hindenburg]] (left) and [[Erich Ludendorff]]]]

[[File:Generalfeldmarschall_von_Hindenburg_und_General_Ludendorff.png|thumb|270px|right|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.<ref>Tuchman, p. 334-38.</ref>  

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.<ref>Tuchman, p. 334-38.</ref>  

==Opening Phase: August 23-26==

==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.

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.

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.   

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).

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==

==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.

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 division, 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.

[[File:Bundesarchiv Bild 183-R36715, Ostpreußen, deutsche Infanterie auf dem Marsch.jpg|thumb|220px|right|German soldiers at the Battle of Tannenberg]]

[[File:Bundesarchiv Bild 183-R36715, Ostpreußen, deutsche Infanterie auf dem Marsch.jpg|thumb|220px|right|German soldiers at the Battle of Tannenberg]]

==Aftermath==

==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.

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."<ref>Max Hoffmann, ''War Diaries and Other Papers'' (1929), Vol. I, p. 41. Other spectators at Eighth Army headquarters during this time noted that Ludendorff came to expect nightly copies of intercepted Russian messages and would check with his radio operators if they were delayed.</ref>

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."<ref>Max Hoffmann, ''War Diaries and Other Papers'' (1929), Vol. I, p. 41. Other spectators at Eighth Army headquarters during this time noted that Ludendorff came to expect nightly copies of intercepted Russian messages and would check with his radio operators if they were delayed.</ref>