<Li> b . ^ Renamed Petrograd in 1914 . </Li> <Li> c . ^ Russia continued to use the Julian calendar until after the collapse of the empire (see Old Style and New Style dates). </Li> <P> The Russian Empire (Russian: Россійская Имперія, tr . Rossiyskaya Imperiya) or simply Russia (Russian: Россія, tr . Rossiya) was an empire that existed across Eurasia and North America from 1721, following the end of the Great Northern War, until the Republic was proclaimed by the Provisional Government that took power after the February Revolution of 1917 . </P> <P> The third largest empire 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 empire constructed by russia between 1500 and 1800 finally collapse