The Russian Empire (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 Soviet Union. It was one of the largest empires the world had seen. At one point in 1866, it stretched from 
eastern Europe, across northern Asia, and into North America. At the beginning of the 19th century, Russia was the 
largest country in the world, extending from the Arctic Ocean to the north to the Black Sea on the south, from the 
Baltic Sea on the west to the Pacific Ocean on the east. Across this vast realm were scattered the Tsar's 150 
million subjects, from poor, illiterate peasants to the noble families of great wealth. Its government, ruled by 
the Tsar, was one of the last absolute monarchies left in Europe.

The Russian Empire was a natural successor to the Tsardom of Muscovy. 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 when Peter acceeded to the throne in early 1682.

The administrative boundaries of European Russia, apart from Finland, coincided broadly with the natural limits of 
the East-European plains. In the North it met the Arctic Ocean; the islands of Novaya Zemlya, Kolguyev and Vaigach 
also belonged to it, but the Kara Sea was reckoned to Siberia. To the East it had the Asiatic dominions of the 
empire, Siberia and the Kyrgyz steppes, from both of which it was separated by the Ural Mountains, the Ural River 
and the Caspian Sea — the administrative boundary, however, partly extending into Asia on the Siberian slope of the
Urals. To the South it had the Black Sea and Caucasus, being separated from the latter by the Manych depression, 
which in Post-Pliocene times connected the Sea of Azov with the Caspian. The West boundary was purely conventional:
it crossed the peninsula of Kola from the Varangerfjord to the Gulf of Bothnia; thence it ran to the Kurisches 
Haff in the southern Baltic, and thence to the mouth of the Danube. From the Danube, it took a great circular sweep
to the West to embrace Poland, and separating Russia from Prussia, Austrian Galicia and Romania.

