In 1985 Mikhail Gorbachev became the youngest leader of the Soviet Union and embarked upon a radical series of political, economic, and social reform, promising “perestroika” (restructuring) and “glasnost” (openness). He established good relations with the West and agreed two major arms limitation treaties. These and his sanctioning of the end of the Communist monopoly in Eastern Europe effectively ended the Cold War and in 1990 he was awarded the Nobel Peace Prize.
But perestroika failed to deliver significant improvement in the Soviet economy, and the USSR began to disintegrate. In 1991 he survived a hardline coup thanks primarily to the resistance of Russian president Boris Yeltsin, but was forced to accelerate the pace of change. By the end of the year the Soviet Union ceased to exist and Gorbachev resigned