Hello there. Your question seems to be related to school work, so we just want to remind you, and any potential respondents, that our rules DO permit people to ask for help with their homework, so long as they are seeking clarification or resources, rather than the answer itself. This policy is further explained in this META Thread.

Additionally, while our users may be able to help you out here, we hope that you also will take the time to check out our six-part series, "Finding and Understanding Sources", which should hopefully prove to be helpful for you as you continue in your research.

This is a very contentious question with no real correct answer.

Herbert Feis notes how one British Historian argued that the Cold War started with the British/Russian tension in the 19th century Afghanistan war.

Others see it being the Russian Revolution in 1917 and the rise of the Bolshoviks or with their 1922 success in the Russian civil war.

After the end of the Second World War, there are numerous dates that can be seen as the start of the Cold War. Be it February 46 when Stalin gave his election speech foreseeing war between the Soviet Union and the west as inevitable and George F Kennan publishes his Long Telegram. On the 6th March Churchill gives his foulton speech and the Soviets refuse to follow the British out of Iran.

In 47 we see Britain and America untie their zones of control in Germany to help increase it's economy. Britain then convinces Truman and Marshall to increase aid first to Greece and then to the rest of Western Europe in order to increase prosperity and prevent the spread of communism. The Soviet Union then establishes the COMINFORM to promote the spread of communism.

Come 1948 and the Berlin blockade, the Cold War is already underway.

As you can see, their is no real definitive answer as to when the cold war started. After writing two dissertations on the matter, my own opinion is that their are a number of cold wars packaged into what many call THE Cold War. Communism was seen as a threat by the British from the revolution of 1917. With the rise of Hitler and WW2, it lost its dominance but once the war ended, the west was faced with a strong and large Soviet military looking to suppress Germany as it had been the case of two invasions in less than 50 years. The UK and US wanted a strong Germany as the former did not have the means to support it and the latter did not have the will.

The British done an outstanding job in convincing Truman that Europe was a peril of communism and that a red Europe would have dire consequences for the US, notably in a lack of trading partners. What started as a economic issue soon became a political one and very nearly a military issue.