Development of the Eastern Bloc
Socialism had been gaining momentum among working class citizens of the world since the 19th century. These culminated in the early 20th century when several states and colonies formed their own communist parties. Many of the countries involved had hierarchical structures with monarchic governments and aristocratic social structures with an established nobility. Socialism was undesirable within the circles of the ruling classes (which had begun to include industrial business leaders) in the late 19th/early 20th century states; as such, communism was repressed. Its champions suffered persecution while people were discouraged from adopting it. This had been the practice even in states which identified as exercising a multi-party system.
The Russian Revolution of 1917 saw the first communist state in the Union of Soviet Socialist Republics (USSR), when the Bolsheviks overthrew the provisional government.
During the period between the world wars, communism had been on the rise in many parts of the world, especially in towns and cities. This led to a series of purges in many countries to stifle the movement. Violent resistance to this repression led to an increase in support for communism in Central and Eastern Europe.
In the early stages of World War II, both Nazi Germany and the USSR invaded and occupied the countries of Eastern Europe after the Molotov–Ribbentrop Pact. Germany then turned against and invaded the USSR: the battles of this Eastern Front were the largest in history. The USSR joined with the Allies and in conferences at Tehran and Yalta, the Allies agreed that Central and Eastern Europe would be in the "Soviet sphere of political influence.". The USSR fought the Germans to a standstill and finally began driving them back, reaching Berlin before the end of the war. Nazi ideology was violently anti-communist, and the Nazis brutally suppressed communist movements in the countries it occupied. Communists played a large part in the resistance to the Nazis in these countries. As the Soviets forced the Germans back, they assumed temporary control of these devastated areas.
After World War II, the Soviets ensured that communists loyal to Moscow took power in the countries it occupied. The Soviets retained troops throughout these territories. The Cold War saw these states, bound together by the Warsaw Pact, have continuing tensions with the capitalist west, bound together by NATO. The Chinese Revolution established communism in China in 1949.
During the Hungarian Revolution of 1956, a spontaneous nationwide anti-authoritarian revolt, the Soviet Union invaded Hungary to assert control. Similarly, in 1968, the USSR repressed the Prague Spring by organizing the Warsaw Pact invasion of Czechoslovakia.
Emergence of Solidarity in Poland
Labour turmoil in Poland during 1980 had led to the formation of the independent trade union, Solidarity, led by Lech Wałęsa, which over time became a political force. On 13 December 1981, Polish Prime Minister Wojciech Jaruzelski started a crackdown on Solidarity by declaring martial law in Poland, suspending the union, and temporarily imprisoning all of its leaders.
Although several Eastern bloc countries had attempted some abortive, limited economic and political reform since the 1950s (e.g. the Hungarian Revolution of 1956 and Prague Spring of 1968), the ascension of reform-minded Soviet leader Mikhail Gorbachev in 1985 signaled the trend toward greater liberalization. During the mid-1980s, a younger generation of Soviet apparatchiks, led by Gorbachev, began advocating fundamental reform in order to reverse years of Brezhnev stagnation. After decades of growth, the Soviet Union was now facing a period of severe economic decline and needed Western technology and credits to make up for its increasing backwardness. The costs of maintaining its military, the KGB, subsidies to foreign client states etc., further strained the moribund Soviet economy.
The first signs of major reform came in 1986 when Gorbachev launched a policy of glasnost (openness) in the Soviet Union, and emphasized the need for perestroika (economic restructuring). By the spring of 1989, the Soviet Union had not only experienced lively media debate, but had also held its first multi-candidate elections in the newly established Congress of People's Deputies. While glasnost ostensibly advocated openness and political criticism, these were only permitted within a narrow spectrum dictated by the state. The general public in the Eastern bloc was still subject to secret police and political repression.
Gorbachev urged his Central and Southeast European counterparts to imitate perestroika and glasnost in their own countries. However, while reformists in Hungary and Poland were emboldened by the force of liberalization spreading from the east, other Eastern bloc countries remained openly skeptical and demonstrated aversion to reform. Believing Gorbachev's reform initiatives would be short-lived, hardline communist rulers like East Germany's Erich Honecker, Bulgaria's Todor Zhivkov, Czechoslovakia's Gustáv Husák and Romania's Nicolae Ceauşescu obstinately ignored the calls for change. "When your neighbor puts up new wallpaper, it doesn't mean you have to too," declared one East German politburo member.