The Iron Curtain
On March 5 1946, Winston Churchill held a speech in Westminster College, Fulton, Missouri (not to be confused with Westminster, London). He described eastern Europe as in a "Soviet sphere", being behind "an iron curtain". (Today the term is often used about the Berlin wall, which of course was a very small part of it, and deep within DDR as well.)
From Stettin in the Baltic to Trieste in the Adriatic an iron curtain has descended across the Continent. Behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia; all these famous cities and the populations around them lie in what I must call the Soviet sphere, and all are subject, in one form or another, not only to Soviet influence but to a very high and in some cases increasing measure of control from Moscow.
So, where's the factoid? Actually, he used the same phrase almost a year earlier, in a telegram sent May 12 1945 to president Truman, where he warned him for the Russians with which he had just celebrated the victory over the Germans:
An iron curtain is drawn down upon their frontier. We do not know what is going on behind.
And a few months before, 25 February 1945, this gentleman described the border to the reds as "an iron curtain":
If the German people lay down their weapons, the Soviets, according to the agreement between Roosevelt, Churchill and Stalin, would occupy all of East and Southeast Europe along with the greater part of the Reich. An iron curtain would fall over this enormous territory controlled by the Soviet Union, behind which nations would be slaughtered.
Joseph Goebbels in Das Jahr 2000 (Year 2000)
As early as 1923 the term is used in the title of a Swedish book. Per Emil Brusewitz was a social democrat who leaned quite heavily towards communism - I haven't found any actual quotes from this book, but people who have read it have told me it doesn't elaborate on the title; which would indicate such elaboration wasn't necessary. (The subtitle, On motorcycle Petrograd-Tiflis, indicates this could be some interesting reading indeed.)
The first use of the term in English has been found in a book published in 1920. Ethel Snowden - suffragette, christian socialist, peace worker etc. - had spent some time in the country after the revolution, and wrote about it in Through Bolshevik Russia. She apparently disliked a lot of what she saw, but the curtain is not attributed to the Bolsheviks:
Through 1919 the Allies had maintained an 'iron curtain' around the country, making it virtually impossible to enter or leave.
The very first time a communist iron curtain is mentioned is, however, in a Russian text: Vasily Rozanov (1856-1919) wrote in 1918 (the year after the October Revolution in November 1917) in The Apocalypse of Our Time, Apokalipsis nashego vremeni:
Rattling, creaking and screeching, an iron curtain descends over the Russian history...
Non-soviet iron curtains
Actual iron curtains were used in theaters to prevent fires from spreading (a very real danger, which several horrible incidents prove). These are often called "fire curtains" or "safety curtains" in USA, which has led some people to think that Churchills "iron curtain" is somehow another term; but in the UK they are indeed called "iron curtains". Asbestos was used as well.
The metaphorical curtain has quite a history.
That would be like confessing, and like an iron curtain something fell down between him and his friends.
August Strindberg (1898)
It became evident that Redwood had still imperfectly apprehended the fact that an iron curtain had dropped between him and the outer world.
H. G. Wells (1904)
During World War I the term was used for concentrated artillery fire:
The "rideau de fer" is simply the French method of converging artillery fire upon a single point where they intend to attack or where they are being attacked. [...] As I walked over this section after the curtain had been lifted, I was absolutely baffled for descriptive words. All the earth in that vicinity seemed battered out of shape. The dead needed no burial there.
Whyte Williams, New York Times, 2 June 1915
I don't know if this meaning of the term was indeed coined in France, but it was eventually used in the German press as well. The "iron curtain" was, thus, used for borders and divisions in general well before World War I, but - as far as I've found - more so after.
"What we Germans wish," continued Dr. Stresemann, "is that this iron curtain shall no longer hang between France and Germany [...]
The German foreign minister in his Reichstag about the Rhineland,
Many of the expressions of the terror are certainly hidden behind the iron curtain, that closes off our connections with the world of oppression.
Richard Sandler (prime minister of Sweden 1925-26), 1928
The British press is an iron curtain hiding the real opinion and feelings of the British people, as well as their hopes and their fears.
Nazi newspaper Volkischer Beobachter
During the four years while I was interned in Croatia by the Germans I saw how the Partisans were lowering an iron curtain over Yugoslavia so that nobody could know what went on behind it.
Dr. Vladimir Matchek, New York Times 23 July 1945
Dr. Matchek was the leader of "The famous Yugoslav Croatian Peasant Party", the article's headline reads Matchek predicts Tito dictatorship.
These quotes is just a fraction of what I found, and I didn't dig very deep. The metaphor was obviously in use well before Churchill's speech, and only then got irrevocably associated with the Soviet "sphere".