Tannenberg 1914 by John Sweetman
In 1914 Russia's doomed Tsar, Nicholas II, ordered his armies to invade German territory as soon as they had mobilized. They moved faster than the Germans gave them credit for and panic stories of Cossacks running amok in East Prussia led the German High Command to call back two army corps from the invasion of France. The two Russian armies involved in the attack were led by generals that hated each other more than the Germans; their lack of cooperation and signal staff's tendency to transmit radio messages without bothering to encode them helped the Germans plan and execute a massive ambush. The Russian 2nd Army was annihilated and the Tsarist forces never recovered the initiative until their defeat in 1917.