Russian Empire
Though the Empire was only officially proclaimed by Tsar Peter I following the Treaty of Nystad (1721), some historians would argue that it was truly born either when Ivan III of Russia conquered Veliky Novgorod in 1478, or when Ivan the Terrible conquered the Khanate of Kazan in 1552. According to another point of view, the term "Tsardom", which was used after the coronation of Ivan IV in 1547, was already a contemporary Russian word for empire.
Russian Empire
The third largest empire in world history, at its greatest extent stretching over three continents, Europe, Asia, and North America, 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.