Germany fought a second offensive against the Russian Army in the Masurian Lakes region of East Prussia (now Poland) in February 1915.
Combined with attacks further south, it was part of Field Marshal Hindenburg’s plan for a series of blows aimed at encircling Russian forces on the Eastern Front and knocking them out of the First World War.
The first large-scale attempt to use poison gas as a weapon took place in the run-up to the campaign.
German troops fired shells filled with tear gas at the Battle of Bolimov in Poland on January 31st 1915, to little effect in the freezing temperatures.
A week later, on February 7th, the Germany Army launched a surprise attack on the Russians during a snowstorm in the Masurian Lakes.
The Russians were driven back 70 miles (113 kilometres) in a matter of days. Despite suffering heavy casualties, they successfully counter-attacked on February 22nd, halting the German advance and ending the Second Battle of the Masurian Lakes.
Lethal chemical weapons were used by both the German and British armies later in the First World War, starting with the German offensive at Ypres in April 1915.
Sources: Wikipedia/various
Images courtesy of the Imperial War Museum © IWM (Q 87572)
Posted by: Peter Alhadeff, Centenary News