In early 1915 the Central Powers had a grand design: a coordinated attack through East Prussia by Germany and in Galicia by Austro-Hungary to meet east of the Vistula, enveloping the Russian armies on the eastern front. On 7 February in severe winter conditions the German 8th and 10th Armies began to spring the northern arm of the trap in Masuria. Despite rapid German advances, the town of Lyck held out for four days, and three of the four Russian corps at risk managed to flee to safety in the fortresses of Grodno and Dlita. 100,000 Russian prisoners were taken, but the bulk of their army had survived and assumed a new defensive position east of the Niemen River. The southern arm of the offensive resulted in complete failure for the Austro-Hungarian army, and the loss of the key stronghold of Przemysl.
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