There are many different events in Russia during the years of the war. First of all, the Tsar was removed from the government. Up until this event, the Tsar was considered to be the ultimate ruler, answering only to God and not to the people.
After Tsar Nicholas was deposed, a new government formed. The leader of this new style of government (Communism) was Vladimir Lenin. The new government was a complete change from what the Russians were used to. This government would last from 1917 until the late 1990s.