A hitherto unknown piece of music composed by Wolfgang Amadeus Mozart (Wolfgang Amadeus Mozart) when he was probably in his teens has been discovered in a German library.

Researchers found the composition titled “Ganz kleine Nachtmusik” (Little Night Music) in the German city’s music library while compiling the latest edition of the Köchel Catalogue, the master composer’s archive of musical works.

According to the Leipzig Municipal Library’s announcement the work is approximately 12 minutes long and dates from the mid to late 1760s.

The composition consists of seven smaller parts for string trio.

The manuscript was not written by Mozart himself, but is believed to be a copy made around 1780.

It is written in dark brown ink on white handmade paper and its parts are each bound separately.

The child prodigy of classical music was born in 1756 in Vienna and began composing music at a very young age under the guidance of his father, as reported by the Guardian.

“Little Night Music”, was already presented in Salzburg, at the unveiling of the new Köchel Catalogue, and will follow its debut at the Leipzig Opera on Saturday.

The Köchel Catalog describes it as a piece of music that “comes from a single source and the composer’s attribution suggests that the work was written before Mozart’s first trip to Italy”.