Researchers in Germany say they have unearthed two previously unknown manuscripts written by Johann Sebastian Bach when he was a teenage organist.
Experts say the composer's script was quite distinctive
The handwritten manuscripts, dating from about 1700, are copies of organ music composed by Dietrich Buxtehude and Johann Adam Reinken.
At the time Bach was 15 - and these are the oldest known manuscripts by him.
They were among archives taken from a library in Weimar, east Germany, which was ravaged by a fire two years ago.
The Bach manuscripts survived because they were stored in the building's vault.
The fire at the Duchess Anna Amalia Library, part of a 16th-Century palace, destroyed about 50,000 books.
Bach's life illuminated
According to Bach experts Michael Maul and Peter Wollny from the Bach-Archiv foundation in Leipzig, the manuscripts shed new light on the career of the young Bach.
They confirm that he was a student of the organist Georg Boehm in the north German city of Lueneburg.
The researchers say the latest find is more significant than the discovery last year of a previously unknown vocal piece by Bach, which was also among the papers removed from the library.
Bach's script was quite distinctive, the researchers said, although there was some similarity to Boehm's.
The organ works that Bach copied were chorale fantasias called Nun freut euch lieben Christen gmein (Be joyful ye Christians) and An den Wasserfluessen Babylons (By the waters of Babylon).
The Bach Archiv foundation said that "technically highly demanding, these organ works document the extraordinary virtuoso skills of the young Bach as well as his efforts to master the most ambitious and complex pieces of the entire organ repertoire".