Harry Truman was still in the White House when Ian Paisley began his extraordinary public life - the first of 11 US leaders whose presidential terms his career would span.
There can be few politicians left anywhere on earth who are contemporaries of the man who ordered the atomic bombing of Hiroshima, and yet, even though he is aged over 80 now, Ian Paisley is still going strong.
Paisley spoke with humility and directness on his faith
So the task of compiling a profile of the man who founded his own church and his own political party is a daunting one.
What after all can be left to say about a man who has spent 56 years under the closest scrutiny on the public stage, a pivotal figure around whom the turbulence of Northern Ireland's darkest days rose, and then receded.
The answer turned out to be rather a lot. We met in Ballymena, his political and religious heartland in the middle of what for him turned out to be another successful election campaign.
He was genial and reflective, talking about how he learned the art of public speaking, how his mother helped to shape his faith, and how he prays even for the political opponents he is always castigating with such force and brilliance.
Listen in particular to his amused reaction at the suggestion that he has been something of a revolutionary figure within the worlds of politics and religion.
If you are familiar with the bombast of Ian Paisley the politician, you might be surprised by the humility and directness with which he speaks of his faith.
'More complex and subtle'
In politics, Ian Paisley was always a mercurial figure - he rose to prominence as he conjured the genie of Protestant resistance to change in the 1960s.
To Catholics who stood to benefit from the changes he opposed, he was simply a bigot, determined to "keep them down".
But in reality, the explanation of Ian Paisley's extraordinary longevity is more complex and subtle than that.
He was "not by any means a conventional unionist leader"
He always claimed to be able to dislike Catholicism without disliking individual Catholics, and he was not by any means a conventional unionist leader of the sort who'd dominated Northern Ireland's politics until he burst onto the scene.
Northern Ireland's Protestants were led in those days by "Big House Unionists", that is to say, members of the landowning classes.
Ian Paisley was providing a voice for working-class Protestants who lived in little houses, and in his own way he was a radical, anti-establishment figure - even though that's not how he looked to his Catholic opponents.
A single moment in late 1966, in a sense, sums up the curious combination of truculence and scholarship that Paisley has always brought to his two great goals - protecting the cause of Protestantism, and "keeping Ulster British".
His campaign to stop the well-meaning old Etonian unionist Prime Minister Terence O'Neill from reaching out to the Catholic minority landed him in jail.
While he was in prison on a public order charge, he wrote a well-regarded commentary on one of the letters of St Paul.
How many politicians of the last 500 years could that sentence describe - probably only Ian Paisley.
And there is a paradox at the heart of Ian Paisley's career - he has never really succeeded in de-railing any of the changes against which he has railed.
Ian Paisley (left) 'prays for his political opponents'
The roaring denunciation of the 1985 Anglo-Irish Agreement - in which he booms "Never, never, never, never..." - is perhaps his greatest piece of oratory and you'll hear it in the programme.
But it never dislodged the Anglo-Irish Agreement. Nevertheless, the skill with which he's articulated "unionist pain", has made him the undisputed leader of Ulster Protestantism.
That means of course that he now has to make the kind of decisions over which he once castigated more moderate unionist leaders like O'Neill, Faulkner and Trimble - when and in what circumstances to share power with parties representing Catholics.
You won't hear a definitive answer in our programme about what Ian Paisley is going to do next, but I think you will come away from it with a much better feel for the private man behind that public decision on which Northern Ireland's future now depends.