History of Russia
The war ended in 1721 when an exhausted Sweden sued for peace with Russia. Peter acquired four provinces situated south and east of the Gulf of Finland, thus securing his coveted access to the sea. There, in 1703, he had already founded the city that was to become Russia's new capital, Saint Petersburg, as a "window opened upon Europe" to replace Moscow, long Russia's cultural center. Russian intervention in the Commonwealth marked, with the Silent Sejm, the beginning of a 200-year domination of that region by the Russian Empire. In celebration of his conquests, Peter assumed the title of emperor, and the Russian Tsardom officially became the Russian Empire in 1721.
Russian entry into World War I
On 30 July, Russia declared general mobilisation in support of Serbia; on 1 August, Germany declared war on Russia, followed by Austria-Hungary on 6th. Russia and the Entente declared war on the Ottoman Empire in November 1914, after Ottoman warships bombarded the Black Sea port of Odessa in late October. Unlike its Allies, Russia's Empire was one contiguous landmass but it also considered itself the defender of its fellow Slavs in countries like Serbia.