CHICHESTER, England -- One historian called it the discovery of a lifetime: a priceless handwritten parchment copy of the Declaration of Independence. Beyond rare, the only one like it is the 1776 copy kept under glass at the National Archives in Washington, D.C.

“We certainly weren’t looking for a copy of the declaration like this,” Harvard researcher Emily Sneff said. She and Harvard professor Danielle Allen came upon it while searching the globe for every known edition of the declaration, reports CBS News correspondent Charlie D’Agata.

“Nobody even had an inkling that a second one might exist, and so therefore there was no reason to look for such a thing,” Allen said.

Harvard University researchers say they’ve discovered a second parchment copy of the Declaration of Independence AP

They believe it was penned in America in the 1780s, probably commissioned by James Wilson, portrayed as a flip-flopper in the movie, “1776,” but a fervent nationalist.

There is a difference in this copy that drills down into the very foundation of the nation. The signatures are in no particular order, rather than listed by state, as in the 1776 copy.

“It goes to the heart of the American political order: does the American political order rest on a single national people or on treaties among several states?” Allen said.

The researchers believe the document originally belonged to the Duke of Richmond, known as the “Radical Duke,” for the support he gave to American revolutionaries. It was handed down over generations of dukes until a local man handed it into the records office in the 1950s.

Considering its historical magnitude, it hadn’t been treated well. It had even been folded into a small square. But for Sneff, it was a thing of beauty.

“Being able to go to West Sussex and hold this parchment in our hands, to look at it closely, was just extraordinary,” Sneff said.