Battle of Tannenberg - Prelude

Prelude

During the first weeks of the war the situation developed largely according to the German plan. The Germans had moved up about half of the units of the Eighth Army, reinforced by small groups of the Königsberg garrison, to positions east of Königsberg near the border. The Battle of Stallupönen, a small engagement by the German I Corps under Hermann von François was successful. Nevertheless, the German theater commander, General Maximilian von Prittwitz, ordered a withdrawal towards Gumbinnen. A counterattack planned for 20 August had a fair chance of succeeding but François attacked prematurely, before Mackensen's XVII Corps and Below's I Reserve Corps arrived at their positions. Thus alerted to German intentions the Russians moved up their heavy artillery and were able to turn the attack into a disordered retreat. The Battle of Gumbinnen forced the Germans, in many cases via rail, to take positions south of Königsberg.

Concerned by the defeat at Gumbinnen and the continued advance of the Russian Second Army from the south, Prittwitz ordered a retreat to the Vistula, effectively abandoning East Prussia. When he heard of this, Helmuth von Moltke, the German Army Chief of Staff, recalled Prittwitz and his deputy to Berlin. They were replaced by Paul von Hindenburg, called out of retirement, with Erich Ludendorff as his chief of staff.

Things were not quite as dire as they seemed to the German commanders in Berlin. The two Russian commanders had disliked each other since Samsonov had publicly complained about Rennenkampf's behavior at the Battle of Mukden in 1905. Although the common belief that the two generals had come to blows at a railway station has proved to be incorrect, Rennenkampf would not be inclined to help Samsonov except under dire circumstances. Additionally, Samsonov's Second Army was having serious problems moving forward due to poor supply preparations, and unknown to him, Rennenkampf had decided to delay the First Army's advance to regroup after Gumbinnen, believing the Germans were preparing another attack.

Nevertheless, the scale of the forces deployed still meant the Russians had the upper hand. As they were currently deployed, the German Eighth Army could not even cover the front along Samsonov's line of march, leaving Samsonov's left wing free to advance without opposition. Unless troops from the Königsberg area (I, XVII and I Reserve Corps) could be moved to check this advance, the Germans were in serious danger of being cut off.