Mr Holzer, who has written more than 40 books on Lincoln and the Civil War, made his assessment after trawling reports of the president’s speaking tours, eyewitness accounts and newspaper commentaries.
His conclusion was that Lincoln was most certainly a tenor.
During earlier research, Mr Holzer found that many first-person accounts of Lincoln’s public speaking were always revealed surprise at his initial sound and appearance.
He said: ‘They all seem to say, for the first ten minutes I couldn’t believe the way he looked, the way he sounded, his accent.
‘But after ten minutes, the flash of his eyes, the ease of his presentation overcame all doubts, and I was enraptured.’
If we could hear Lincoln today, it wouldn’t only be the pitch of his voice that would surprise us. The way he pronounced his words would also come as a shock. Here is how Civil War diarist George Templeton Strong recorded Lincoln’s recounting of an anecdote:
‘Wa-al,’ says Abe Lincoln, ‘that reminds me of a party of Methodist parsons that was travelling in Illinois when I was a boy thar and had a branch to cross that was pretty bad—ugly to cross, ye know, because the water was up. And they got considerin’ and discussin’ how they should git across it, and they talked about for two hours, and one on ‘em thought they had ought to cross one way when they got there, and another another way, and they got quarrellin’ about it, till at last an old brother put in, and he says, says he, “Brethren, this here talk ain’t no use. I never cross a river until I come to it.”’