International Mozarteum Foundation research head Ulrich Leisinger said the sheet music found in the French city of Nantes was undoubtedly created by the late classical composer, The Daily Mail said Friday.
"His handwriting is clearly identifiable. There's no doubt that this is an original piece handwritten by Mozart," the official from the Austrian foundation said.
The sheet music, thought to have been a preliminary draft by Mozart, was found at the Nantes library during a recent archive reorganization effort.
Leisinger has dated the Mozart sheet music to sometime between 1787-91 and said the historical item could be worth hundreds of thousands of dollars if put up for sale.
"The fact that an entirely new sheet shows up is extremely rare," he told the Daily Mail.