The Eastern Front was the vast theatre of the First World War that took place between Russia, Austria-Hungary and Germany. All three countries expected conflict in this area. The German Schlieffen Plan assumed an invasion of Russia and the Russian Army had its own Plan 19, that involved an attack on Germany.

General Alexander Samsonov was given command of the Russian Second Army for the invasion of East Prussia in August, 1914. He advanced slowly into the south western corner of the province with the intention of linking up with General Paul von Rennenkampf advancing from the north east.

General Paul von Hindenburg and General Erich Ludendorff were sent forward to meet Samsonov's advancing troops. They made contact on 22nd August and for six days the Russians, with their superior numbers, had a few successes. However, by 29th August, Samsanov's Second Army was surrounded. General Alexander Samsonov attempted to retreat but now in a German cordon, most of his troops were slaughtered or captured. Only 10,000 of the 150,000 Russian soldiers managed to escape. Shocked by the disastrous outcome of the Battle of Tanneberg Samsonov committed suicide.

The slow Russia invasions of Galicia were more successful against the poorly organised Austro-Hungarian Army. Eventually Austria-Hungary ordered a counter-attack at Komarow. After initial progress, the Austro-Hungarian troops were forced to retreat to the Carpathian Mountains. The German attack, led by General Erich Ludendorff, on the Russian Army at Lodz, inflicted heavy casualties.

In September, 1915, Russian forces were driven from Galicia. By this stage it was estimated that the Russian Army had lost over 2 million men in six months. General Erich Falkenhayn, Chief of Staff of the German Army, considered the Russians had been badly damaged but decided they could not be beaten and brought a halt to the offensive. Instead, German forces were concentrated on the Western Front at Verdun.

Attacks by the Central Powers on Russia were resumed in the autumn of 1916. By the end of the war it was estimated that the Russian Army had lost another million men. The failed Russian Kerenski Offensive in July, 1917, broke both the army and the will of the government. The October Revolution brought Lenin to power in Russia. The Bolshevik government immediately entered into negotiations and fighting on the Eastern Front officially ended on 16th December, 1917.