What event triggered the US to issue the Truman doctrine

What events caused the Truman Doctrine? The Truman Doctrine was an American foreign policy created to counter Soviet geopolitical spread during the Cold War. It was first announced to Congress by President Harry S. Truman on March 12, 1947 : 547-9 and further developed on July 12, 1948 when he pledged to contain Soviet threats to Greece and Turkey.