The Cold War was a period of rivalry, without direct fighting between the two main powers, between the United States and the Soviet Union and their allies. This lesson covers the documented events of its origins from 1945 to 1949 and the interpretations historians have attached to them.
It belongs to Core option B study pathways. The next units are containment and Soviet influence in Eastern Europe.
What happened?
- February 1945, Yalta: the Allied leaders met and discussed the post-war arrangement of Europe, including Poland.
- July to August 1945, Potsdam: a further conference, with disagreements about Germany and reparations. The war against Japan ended in August 1945.
- February 1946: an American diplomat in Moscow, George Kennan, sent the “Long Telegram”, an assessment of Soviet policy.
- March 1946: Winston Churchill spoke at Fulton, Missouri, using the image of an “iron curtain” across Europe.
- March 1947: the Truman Doctrine pledged American support for countries resisting pressure, starting with Greece and Turkey.
- June 1947: the Marshall Plan offered economic aid for European recovery. The Soviet side did not take part and pressed its allies in Eastern Europe to decline.
- February 1948: a communist-led takeover of government in Czechoslovakia.
- June 1948 to May 1949: the Berlin blockade and airlift.
- April 1949: the North Atlantic Treaty created NATO.
How have historians interpreted the origins?
- Traditional view: the Soviet Union’s expansion into Eastern Europe and its ideology led the West to respond defensively.
- Revisionist view (for example, William Appleman Williams): American economic and strategic aims, including the search for open markets, helped drive the confrontation.
- Post-revisionist view (for example, John Lewis Gaddis): several factors, including mutual mistrust, security fears and misperception, interacted, with the weight of each disputed.
These are attributed interpretations, built on different evidence and different questions. Describing them is not the same as endorsing any of them.
Worked example: avoid taking a side
Weak: “The Soviet Union was to blame because it took over Eastern Europe.”
Stronger: “Soviet influence in Eastern Europe grew between 1945 and 1948, and the takeover in Czechoslovakia in February 1948 is a documented example. Traditional historians treat this as the main cause of confrontation. Revisionist historians such as William Appleman Williams point to American aims, including economic ones, and argue that Soviet actions were responses. The evidence for each view is different, so the origins are more accurately described as the result of interacting actions rather than the fault of one side.”
The stronger version states a fact, attributes two views and draws a qualified conclusion.
What mistake do students make?
They use modern political labels as if they were evidence, for example describing one side as the “good” side. History answers are marked on supported reasoning. Replace the label with the actions: what was announced, signed or done, by whom and when.
Check yourself
1. Put in order: Truman Doctrine, Berlin blockade begins, NATO founded, Marshall Plan announced.
Show answer
Truman Doctrine (March 1947), Marshall Plan announced (June 1947), Berlin blockade begins (June 1948), NATO founded (April 1949).
2. Match each view to its emphasis: traditional, revisionist.
Show answer
Traditional stresses Soviet expansion. Revisionist stresses American economic and strategic aims. Both are interpretations and should be attributed.
3. Rewrite to avoid taking a side: “The Marshall Plan was a generous gift.”
Show answer
“The Marshall Plan offered economic aid for European recovery in 1947. American officials described it as support for recovery, while some historians argue it also served American economic and strategic interests.”
Where this leads next
Move to United States containment, then compare accounts with the source comparison lesson. The practice set includes a Cold War question. For help writing balanced answers, see our online one-to-one History tuition.