The two telegrams - Kennan's and Novikov's - set the scene for the Cold War in Europe.
The Americans rejected a policy of rollback, which would have been much more aggressive and confrontational and would have seen international relations deteriorate at a rapid pace.
A rollback approach would have involved American intervention to overturn a communist government in another country.
On 5 March 1946, the former British Prime Minister, Winston Churchill, condemned the Soviet expansion in Eastern Europe in his famous Iron Curtain speech.
In the speech, he famously noted that, “from Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the continent.”
Whilst there was no real physical barrier, there was a clear division between the democratic states of the West and the communist states of the East.
Many in the West were concerned that Stalin would not stop in Eastern Europe but would expand his empire further West.
In a nutshell, what Churchill meant by this was that the Allies had spent six years fighting for the freedom from fascism in Europe, only to have half the continent now under Soviet dictatorship.
Churchill’s speech is considered significant; the first time there had been an announcement of the beginning of the Cold War.