Answer:
Between 1956 and 1968, several events occurred in Eastern Europe that threatened communist control. These included the Hungarian Revolution in 1956, the Prague Spring in 1968, and other political and social movements in Poland, East Germany, and other Eastern European countries.
The Soviet Union responded to these events by using military force and political pressure to suppress dissent and maintain communist control. In the case of Hungary, the Soviet Union sent troops to crush the rebellion, resulting in the deaths of thousands of people. Similarly, in Czechoslovakia, the Soviet Union and other Warsaw Pact countries invaded the country to quell the Prague Spring movement.
While the Soviet Union was successful in maintaining communist control over Eastern Europe during this period, it came at a significant cost. The use of military force and suppression of dissent led to significant human rights violations and undermined the legitimacy of the communist governments in the region. Additionally, the Soviet Union's actions were met with widespread international condemnation and further strained relations with Western countries.
In conclusion, while the Soviet Union was able to maintain communist control over Eastern Europe during the period 1956 to 1968, it did so through the use of force and suppression of dissent. The consequences of these actions were significant and had long-lasting effects on the region and international relations.