In February 1947, Britain informed the USA that they could no longer afford to keep troops in Greece and Turkey, which alarmed Truman as these countries were likely to become communist.
Many Eastern European countries had been liberated from Nazi control by the USSR and some, including Poland, had already been forced to take a communist government.
In his speech, Truman said that countries faced a choice between capitalism and communism, stating that communism was evil because the people were not free.
In April 1948, General George C Marshall, the U.S Secretary of State, announced the USA's plan, named after him, which provided 17 billion dollars in Aid to help rebuild Europe.
The Marshall Plan aimed to give people a stake in their own society by providing Aid to 16 countries, with the largest beneficiaries being Britain and France.
Although the Soviet countries did not have enough money to support one another, the consequences of the two countries' plans were clear: a dramatically increased tension between the two sides because Western Europe was now united tied to the US by the Marshall Plan and the USA's policy of containment while the East was also united but under Soviet control.
In the beginning, Comic-Con spent their time organizing credit and trade agreements but after 1953 it began to organize the economies of member states giving each a financial Five-Year Plan.
Comic-Con strengthened the trade links between the common form countries and aimed to provide financial aid in line with communist principles which would prevent the Soviet-led countries joining the Marshall Plan.
The Truman Doctrine was a policy statement that supported Greece in defeating the Communists and confirmed the USA's commitment to containing communism.
The agreement made sure that the governments in the satellite States took their orders from Moscow and the parties were encouraged to trade with each other rather than non-communist countries.
Common form, a part of Comic-Con, was responsible for organizing all the Communist parties in Europe with the aim of removing opposition to Soviet control in communist-led countries.