<Li> c . ^ Russia continued to use the Julian calendar until after the collapse of the empire (see Old Style and New Style dates). </Li> <Tr> <Td_colspan="3"> Warning: Value specified for "continent" does not comply </Td> </Tr> <P> The Russian Empire (also known as Imperial Russia, Tsarist Russia and Pre-revolutionary Russia) was an empire that existed from 1721 until proclamation of the Republic by the Provisional Government that took power after the February Revolution of 1917 . </P> <P> One of the largest empires in world history, stretching over three continents, the Russian Empire was surpassed in landmass only by the British and Mongol empires . The rise of the Russian Empire happened in association with the decline of neighboring rival powers: the Swedish Empire, the Polish--Lithuanian Commonwealth, Persia and the Ottoman Empire . It played a major role in 1812--1814 in defeating Napoleon's ambitions to control Europe and expanded to the west and south . </P>

When did the russian empire start and end