Four precious pages of one of Mozart’s most beloved compositions is found in Budapest.

Mozart’s Piano Sonata in A Major, No. 11 K331 is one of the great musical genius’s most recognisable pieces. Composed in 1783, the score of this iconic keyboard masterwork has been reproduced millions of times in the ensuing 230 years. However aside from a single page, which is preserved in a Salzburg museum in Austria, the composer’s birth place, the original manuscript penned by Mozart was thought lost, until now.

After five years of tirelessly cataloguing previously unidentified historical documents in the Szechenyi Library in Budapest, the institution’s Head of Music, Basazs Mikusi has claimed to have stumbled upon four yellowing pages written in Mozart’s hand.

Basazs Mikusi with the newly discovered manuscript.

Although the purely serendipitous discovery is yet to be corroborated, Mikusi, who is a Mozart scholar, is in no doubt as to the authenticity of the documents. “When I found the manuscript the handwriting was immediately recognisable as Mozart’s” Mikusi said. “My heart started racing when I realised that it was indeed the Sonata in A Major.”

Occasionally letters, small fragments of...