In his "Iron Curtain" speech, delivered exactly 60 years ago, Winston Churchill brilliantly defined an era.
The speech may also have lessons for the present.
Churchill's speech defined the world order for the next 40 years
It was a heroic but troubled time. The world was in turmoil after the most terrible conflict in human history.
On 5 March 1946 Churchill was no longer the UK's prime minister but he still enjoyed a giant reputation around the world.
So US President Harry Truman himself travelled 1,000 miles to Fulton, Missouri, to hear Churchill give a speech after receiving an honorary degree at Westminster College there.
It would become one of the most famous speeches of the century.
Churchill had been mocked in Britain in the 1930s for warning of the menace of war from Nazi Germany, but had been proved right in the end. Now he was about to do it again.
After expressing his admiration for the valiant Russian people and "my wartime comrade, Marshall Stalin", he spoke the words which came to define the oppression, fear and confrontation of the Cold War era:
"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".
It was vintage Churchill - grave, eloquent and ruthlessly honest.
It was a plea to America, already the world's greatest superpower, to acknowledge the harsh reality about Stalin - that on his orders the Russians were in the process of imposing totalitarian rule by communist governments in all the countries under their military control.
America had long been reluctant to accept this conclusion. But by the following year President Truman had decided on a policy of containment of Soviet power.
In 1948 any remaining doubts were removed by the communist takeover in Czechoslovakia and the Berlin Blockade, when the Russians tried but failed to starve West Berlin into submission.
Stalin was furious at the Iron Curtain speech. He called Churchill a "warmonger" and banned its publication in the Soviet Union.
But Churchill's speech was far-sighted.
It clearly prophesied the Cold War, which was to last until the fall of the Berlin Wall in 1989.
During an era of more than 40 years, both East and West lived under the constant threat of devastating nuclear war.
The time of maximum danger may have been the Cuban Missile Crisis of 1962.
The Soviet Red Army used its tanks to quell rebellions in East Germany in 1953, Hungary in 1956 and Czechoslovakia in 1968.
The Soviet grip on its satellites was weakened by Poland's Solidarity revolt in 1980-81.
But few predicted how the Iron Curtain would eventually be torn down - by a series of "people power" revolutions which led to the overthrow of communist regimes across eastern Europe in 1989, followed by the dissolution of the Soviet Union itself in 1991.
The 60th anniversary of the speech has brought many reflections on its relevance for the present.
At Westminster College in Fulton, Missouri, the anniversary weekend was marked by lavish celebrations and calls for free societies to renew their commitment to defending freedom and democracy everywhere.
The legacy of Russian domination survived the fall of the Berlin Wall
The nearby Churchill Memorial Museum and Library has been renovated with high-tech interactive facilities designed to "bring Churchill alive" to a new generation of visitors.
In Hungary and the Czech Republic - two of the nations forced to submit to Soviet domination for nearly half a century - this 60th anniversary comes just a few days after a visit by Russian President Vladimir Putin, which was the first by a Russian leader since Boris Yeltsin in the early 1990s.
The long chill in Russia's relations with its former satellites reflected their determination to escape from Russia's shadow by joining Nato and the European Union.
Their mistrust of Moscow was reinforced by the Russian army's excesses in Chechnya, the Putin government's efforts to influence the political future of Ukraine, and the energy crisis early this year when Russia abruptly cut off gas supplies to Ukraine in a dispute about prices.
President Putin made gestures of conciliation on his tour.
He acknowledged a sense of "moral responsibility" for the Soviet Union's bloody suppression of the 1956 Hungarian Revolution and for its invasion of Czechoslovakia to crush the "Prague Spring".
And he called for a new economic partnership with those countries, free from what he called "artificial political considerations".
Mr Putin insisted that the world must not confuse the old Soviet Union with modern Russia.
But some uncomfortable parallels between the two were drawn during his tour.
In Hungary seven human rights organisations, including Amnesty International, accused Russia of violating democratic standards by persecuting dissidents in the same way as Moscow did during the Cold War.
In Prague, a newspaper published a letter from former President Vaclav Havel and other democratic champions.
It charged Mr Putin's government with using Chechen terrorism as a pretext to take away political freedoms won by Russians when the Soviet Union collapsed.
After all these years Churchill's Iron Curtain speech reads like an example of true statesmanship, and perhaps the most memorable "wake-up call" in post-War history.
It also displays the genius with words that would later bring Churchill yet another honour - the Nobel Prize for Literature.
In an age of great uncertainty it projected Churchill's iron conviction of purpose.
His core beliefs were in the special bond between America and Britain, the need for the United Nations to be "a force for action and not merely a frothing of words", and the duty of the Western democracies to stand up for freedom and against tyranny.
Sixty years later, there are more democratic governments in the world than ever.
Yet such moral certainty is rare, and the authority with which Churchill's expressed it is surely rarer still.