The Battle of the Vistula River, also known as the Battle of Warsaw, was a Russian victory against Germany on the Eastern Front during the First World War.

As the Austro-Hungarian army was being driven from Galicia in the Battle of Lemberg (1914), Paul von Hindenberg, commanding the German forces on the Eastern Front, ordered the an offensive against the Russian lines in the area of Warsaw. The battle opened on September 29 by the Ninth Army commanded by August von Mackensen. Mackensen reached the Vistula River by October 9 and was only 12 miles away from Warsaw. Here the German offensive began to faulter. General Nikolai Ruzsky , commander of the Russian Northwest Front, brought up significant reinforcement against the Ninth Army. At this time Hindenberg learned of a planned Russian offensive into Silesia from a captured Russian soldier. However, Hindenberg continued to push the offensive against Warsaw. The Germans were unfamiliar with the land and unable to bring sufficient reinforcements to the Ninth Army, therefore allowing Ruzsky to concentrate his front against Mackensen. On October 17 Hindenberg ordered a retreat and by the 31st the battle was over.

November 1 the Ninth Army was back where it had began minus 42,000 soldiers. This was the first of a series of attempts by Hindenberg to capture Warsaw. 10 days later Hindenberg made another attempt at Warsaw culminating in the battle of Lodz. Superior numbers on the Eastern Front had given the Russian army the advantage in the fall of 1914.

Source

• Tucker, Spencer The Great War: 1914-18 (1998)