The Russian Empire (Pre-reform Russian orthography: Россійская Имперія, Modern Russian: Российская Империя, translit: Rossiyskaya Imperiya) was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the short-lived Russian Provisional Government, which was succeeded by the Soviet Union. It was one of the largest empires in world history, surpassed in landmass only by the British and Mongol empires: at one point in 1866, it stretched from eastern Europe across Asia and into North America.