In 1946, Harvard Law School Library purchased what it believed to be a damaged and faded copy of the Magna Carta for just US$27. The document came from London legal publishers Sweet & Maxwell, who had obtained it at a Sotheby’s auction a month earlier for £42 from a former First World War pilot.

At the time, it was incorrectly catalogued as a 1327 version created during the reign of Edward III. However, detailed textual analysis and forensic comparisons has confirmed that the once-overlooked “copy” is in fact a genuine Magna Carta from the year 1300, issued under King Edward I.

Although it’s now worth millions, Harvard has no plans to sell the historic artifact.

The Magna Carta was originally established in 1215 under King John and outlined the rights of ordinary people under common law for the first time.

There are four copies of the 1215 issue and seven of the 1300 version, including Harvard’s original. One edition sold for over US$2m at auction in New York back in 2007.

“My reaction was one of amazement and, in a way, awe that I should have managed to find a previously unknown Magna Carta,” David Carpenter, Professor of Medical History at King’s College London, said about the “fantastic discovery”.

He teamed up with Nicholas Vincent, Professor of Medieval History at the University of East Anglia, to confirm the authenticity of the Harvard document. He said Harvard’s Magna Carta is the 25^th known surviving original: “The 1300 issue is the last time it was issued as a single sheet document under the king’s seal as an official endorsement of the settlement of Magna Carta.”