The history of the Jews in the Soviet Union is inextricably linked to much earlier expansionist policies of the Russian Empire conquering and ruling the eastern half of the European continent already before the Bolshevik Revolution of 1917. "For two centuries – wrote Zvi Gitelman – millions of Jews had lived under one entity, the Russian Empire and [its successor state] the USSR. They had now come under the jurisdiction of fifteen states, some of which had never existed and others that had passed out of existence in 1939." Before the revolutions of 1989 which resulted in the end of communist rule in Central and Eastern Europe, a number of these now sovereign countries constituted the component republics of the Soviet Union.