The term communism is used in this manual to refer to the system of government prevailing in the Soviet Union between 1917 and 1991 and its allies in Eastern Europe between circa 1947 and 1989. This system was that of a one-party state ruled by a communist party owing allegiance - except for Yugoslavia and, later, Albania - to Moscow. Stalin was instrumental in establishing the official ideology of Marxist-Leninism and in initiating a centrally-planned economy which was exported to all the countries forced into its orbit at the outset of the Cold War. The fall of the Berlin wall in 1989 signalled the end of the Soviet bloc and the Soviet Union itself was dissolved in 1991.