A rare second parchment copy of the Declaration of Independence has been found — in England.

The discovery was made by Harvard University researchers Emily Sneff and Danielle Allen, according to a university news release published in the Harvard Gazette on Friday. The pair located the rare document in a records office in Chichester, a city near the coast of southern England.

The first clue that the document existed came in 2015, when Sneff spotted an unusual listing from a catalog for the West Sussex Record Office in Chichester: “Manuscript copy, on parchment, of the Declaration in Congress of the thirteen United States of America.”

“I’d found vague descriptions of other copies of the Declaration that turned out to be 19th century reproductions of the signed parchment in the National Archives, so that was what I was expecting,” Sneff told the Harvard Gazette. “What struck me as significant was that it said manuscript on parchment.”

The West Sussex Record Office sent over photos of the actual document, which Sneff and Allen pored over.

“When I looked at it closely, I started to see details, like names that weren’t in the right order — John Hancock isn’t listed first, there’s a mark at the top that looks like an erasure, the text has very little punctuation in it — and it’s in a handwriting I hadn’t seen before,” Sneff told the Gazette. “As those details started adding up, I brought it to Danielle’s attention, and we realized this was different from any other copy we had seen.”

Over the last two years, Sneff and Allen, who work with Harvard’s Declaration Resources Project, analyzed the Sussex version of the Declaration of Independence: the handwriting, the parchment itself, the signatories. They have concluded that the “Sussex Declaration” likely dates to the 1780s, was made in New York or Philadelphia and belonged to the Duke of Richmond — also known as the “Radical Duke” for his support of the American Revolution, the Boston Globe reported.

Photos of the newly discovered Declaration show crease marks indicating that it had been folded multiple times at some point.

“Nobody even had an inkling that a second might exist, and so there is no reason to even look for such a thing,” Allen told CBS News.

Sneff and Allen said they trying to determine who commissioned the parchment copy, who actually made the copy and how the document arrived in England, the university said.

The National Archives in Washington has the only other parchment copy of the Declaration of Independence, the original one signed July 4, 1776. What sets the Sussex copy apart from the National Archives copy is that the signatures are not grouped by state, Allen and Sneff told the Harvard Gazette.

Though it is not legally binding like the U.S. Constitution, the Declaration of Independence is one of the most important documents in American history. The second sentence of its weighty preamble — “We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness” — is often quoted.

The original parchment copy of the Declaration of Independence in the National Archives is, alas, severely faded to the point that it’s nearly illegible — and possibly was even defaced, according to experts who have studied it.