Harvard Law School bought a 1327 copy of the Magna Carta from legal book dealer Sweet & Maxwell for $27.50 in 1946. Nearly eight decades later, two researchers have discovered it's actually an original version. On May 15,Harvard announcedthat two British researchers discovered the school's copy is one of the authentic versions of the legal document created in 1300. David Carpenter, a professor of medieval history at King's College London, said in avideo shared by Harvardthat he was looking through the school's digitized manuscript collection when he first saw the copy. "With great excitement I pressed the button to see the digitized image that they put up, and I just thought, 'This looks so much like a 1300 original,'" Carpenter said in the video. Carpenter said he reached out to Nicholas Vincent, professor of medieval history at the University of East Anglia, to ask his opinion. "I think it took all of 30 milliseconds for me to reply, 'You know what that is, and I know what that is,'" Vincent said in the video. HLS librarians said they further scanned the document using ultraviolet light and spectral imaging and sent the visuals to Carpenter and Vincent. "I did check it word by word against all the other originals," Carpenter said in the video shared by Harvard. "At first sight, parts of it are not easy to read. It's faded and blurred." Harvard said in a release that Sweet & Maxwell, a legal books dealer, bought the copy at a Sotheby's auction on behalf of Air Vice-Marshal Forster Maynard, a senior commander in the United Kingdom's Royal Air Force. Sweet & Maxwell purchased it at auction for £42 in December 1945 then sold it to HLS for $27.50 a few months later, the release said. Vincent said in the video shared by Harvard that "whoever catalogued it in 1945 misread the date and therefore assumed that it was a copy." There are only six other original versions of the Magna Carta confirmed by King Edward I in 1300, Carpenter said. Of them, only five are fully intact. The latest discovery makes seven. "I'm completely confident this is an original 1300 confirmation of Magna Carta," Carpenter said. The Magna Carta is a British constitutional document that put into writing the principle that the king and his government was not above the law, according to theUnited Kingdom's Parliament. It was first issued by King John in 1215, and an amended version was issued in 1225. King Edward I confirmed the document in 1297 and again in 1300, according to Harvard. Melina Khan is a national trending reporter for USA TODAY. She can be reached atmelina.khan@usatoday.com. This article originally appeared on USA TODAY:Harvard's Magna Carta copy is a actually an original, researchers say