Russia. After the october revolution and the fall of the Czar.
The Russian Revolution weakened the Allied war effort. Russia pulled out of the war, so the Allies needed help.
Britain, France, Russia, Italy and the United States were members of the Allied Powers. Russia dropped out when the Russian Revolution started. The US was late getting into the war.
Russia pulled out of the war, so the Allies needed help. The Russian Revolution weakened the Allied war effort.
The Allied powers were Britain, France and Russia. However, in 1917 Russia left the war due to the Russian Revolution. Although Italy were meant to be with the Central Powers they swapped sides and fought with the Allies.
Austria, allied with Russia in the late 18th century had come to fear Russian influence in the Balkans. Specially after its defeat by Prussia in 1866.
France first allied with Russia in 1891 with what was known as the Franco-Russian Alliance. Then, in 1904, France signed a "friendly agreement" (the Entente Cordiale) with Britain. Russia left the alliance and the war altogether in 1917, though, and the United States (upset with Germany) subsequently jumped in to aid the Allied forces.
American Expeditionary Forces under Allied auspices were sent to intervene into the Russian Civil War. The Allied forces implicit objectives were to provide support for the loyalists against the Bolshevik revolutionaries.
Russia, Britain and France were allied by the Triple Entente.
They were there as part of the Allied intervention in the Russian Civil War. This article explains: http://en.wikipedia.org/wiki/Allied_Intervention_in_the_Russian_Civil_War
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Russia