The winter of 1917 was one of the coldest of the whole century and the abundant snowfalls forced the various armies to a long halt. But the political and social events of that period cannot be left out because they marked a fundamental turning point for the First World War and for the history of the whole 20th century.
First of all Russia gradually quit the scene of the First World War. The situation in the great eastern empire, in continuous turmoil, in the last years had become untenable: in two and a half years the war had brought about an unprecedented economic crisis and had also caused the loss of some six million men. In February the first popular uprising was unleashed, supported by revolutionary socialist, Menshevik and bolshevist parties and by the liberal committee of the Duma (Parliament), and on 02nd March Czar Nicholas II was deposed. The revolution, ideologically similar to the one that had already taken place in 1905, started in Saint Petersburg, the capital city at that time, and then also spread to other cities such as Moscow. The revolutionaries and the Russian Parliament reached an agreement that aimed at the democratization of the country with the establishment of a new government presided by Prince L'vov. But eight months later a new revolution would radically change things with the birth of the Soviets and the definite exit of Russia from the war (March 1918).
Slightly more than a month after the arrest of Czar Nicholas II, the Democrat President of the United States of America, Woodrow Wilson, declared war against Germany (07th April).
This decision was taken after Germany announced its intention to start an unlimited submarine war in the Atlantic Ocean. This was a very important moment for the destiny of the First World War: in the years of neutrality America had grown considerably thanks to its exports to member countries of the Triple Agreement and, backed by a very strong economy, the USA was able to provide fresh forces and new arms that were to result decisive to the Triple Agreement.
