Austrian Galicia attack on Galicia Tannenberg Masurian Lakes Gorlice–Tarnów offensive Russian-occupied Poland Warsaw Germany Russia Central Powers contributed East Prussia offensive Poland Galicia lice Western Front Prussia France
As previously agreed with France, Russian plans at the start of the war were to simultaneously advance into Austrian Galicia and East Prussia as soon as possible. Although their attack on Galicia was largely successful, and the invasions achieved their aim of forcing Germany to divert troops from the Western Front, the speed of mobilisation meant they did so without much of their heavy equipment and support functions. These weaknesses contributed to Russian defeats at Tannenberg and the Masurian Lakes in August and September 1914, forcing them to withdraw from East Prussia with heavy losses. By spring 1915, they had also retreated from Galicia, and the May 1915 Gorlice–Tarnów offensive then allowed the Central Powers to invade Russian-occupied Poland. On 5 August, the loss of Warsaw forced the Russians to abandon their Polish territories.
