A country comprising the greater portion of eastern Europe and northern Asia. The northern and central portions of European Russia was ruled by Norse dynasties until the Mongol conquest in the 13th century. The southern areas were ruled by a succession of Central Asian peoples. After the 16th century, Muscovy (Moscow) became the center of a resurgent Russian state, which for several hundred years steadily expanded its borders. A major European power after 1700, Russian strength deteriorated in the late 19th and early 20th centuries. Mounting frustrations with the autocratic rule of the tsars and military defeats in World War I brought the fall of the monarchy in March 1917. In November, the liberal Kerensky regime was overthrown by the Bolsheviks (communists) who made peace with Germany and began expanding their power. Anti-Bolshevik forces (the "White Russians") quickly formed throughout the country. White Russian regimes were established in western and southern Russia and throughout Siberia. Bolshevik control was limited to northern and central Europe and Russia. Britain, France, Japan and the United States became involved in the civil war, but the inability of the various White Russian governments to cooperate with each other, or to meet the legitimate needs of the people, made it possible for the Bolshevik Red Army to have generally established Soviet authority by the end of 1920. During the Civil War, these warring governments, along with many municipalities, issued distinctive stamps. During 1920-23, the government consolidated its position. Although a number of border provinces (Poland, Finland, the Baltic States and Bessarabia) were lost, the newly formed Union of Soviet Socialist Republics included almost all of the territory of the old empire. Lenin's death in 1924 precipitated a power struggle within the communist leadership, with Josef Stalin ultimately emerging as the absolute ruler of the country. During the 1920s and early 1930s, Stalin exiled his opponents within the party. From the mid-1930s through 1953, he purged any suspected opposition through show trials and executions. Millions of Russians died.