The 12-minute piece by Austrian composer, Wolfgang Amadeus Mozart, is called "Ganz kleine Nachtmusik" and was likely written when he was a teenager sometime in the mid-to late-1760s. Leipzig Municipal Libraries revealed the good news in a statement and that the piece will have its debut on Saturday at the Leipzig Opera.

The piece believed to have been written by a teen Mozart, "Ganz kleine Nachtmusik," will be performed for the first time at the Leipzig Opera on Saturday (Sept. 21).

The young Mozart had been known to researchers up until now "mainly as a composer of piano music, arias and symphonies", Ulrich Leisinger of the International Mozarteum Foundation

The string trio, probably written in the composer’s teens, was found in a library as archivists compiled an updated catalog of his work