For nearly 250 years, a notebook lay unnoticed until it revealed lost Mozart music

A notebook containing lost Mozart music was discovered at France's National Library in February 2026.

The 44-page manuscript records composition lessons Mozart gave in Paris from May to July 1778 to Marie-Louise-Philippine de Bonnières de Guînes.

It includes seven pieces for flute and harp, six of which survive complete and can now be performed.

The notebook was authenticated by the Mozarteum in Salzburg after being identified by curator François-Pierre Goy and musicologist Laurence Decobert.

The lessons ended when Mademoiselle de Guînes married on 26 July 1778, leaving the notebook unfinished.