The Russian Empire (Pre-reform Russian orthography: Россійская Имперія, Modern Russian: Российская Империя, translit: Rossiyskaya Imperiya) is an empire that rules in Eastern Europe and Upper Asia. In Europe, it is bordered by the Ottoman Empire and Persia to the south, and Sweden, Prussia and the Danubian Federation to the west. It is the successor to the Tsardom of Russia. The Russian Empire is surpassed in landmass only by the British and Mongol empires.