France’s national library, Bibliothèque nationale de France (BnF), has announced the unearthing of a previously unknown manuscript by Wolfgang Amadeus Mozart from its collection.

Page 10 of Mozart’s manuscript. © Élie Ludwig / BnF

Discovered on 2 February by curator François-Pierre Goy, the 44-page notebook contains composition exercises and seven works for flute and harp that Mozart penned during his time in Paris in 1778. The notebook was likely used for composition lessons that the 22-year-old composer gave to harpist Marie-Louise-Philippine de Bonnières de Guînes, daughter of the Duke of Guînes.

After Goy identified the handwriting as Mozart’s, the notebook was validated by the Bibliotheca Mozartiana in April.

“This discovery is, according to specialists, one of the most important of recent decades,” said the library’s President Gilles Pécout.

“It allows us to document Mozart’s last stay in Paris and… reveals to us, in his daily life, the activities of the young [composer] in dialogue with his student. The identification of this autograph confirms the universality of our collections and suggests the promise of new and fruitful international scientific and artistic collaborations, particularly with Austria.”

A flautist, the Duke of Guînes was a patron of Mozart’s who co-commissioned his Concerto for Flute and Harp, K. 299 alongside fellow flautist King Frederick of Prussia. The Duke held ambitions that his daughter’s composition lessons would lead to her composing “grand sonatas” for both of them, the BnF notes; the lessons took place between May and July 1778, concluding with her marriage.

These seven duets – six complete, one unfinished – have been written for a flute which can produce a low C; not within the range of a standard flute at the time, but a characteristic of the Duke of Guînes’s instrument. They were described by Mozart in a letter to his father on 14 May 1778, where he also complains about his studen’ts lack of compositional talent.

The BnF’s Music Department holds the second-largest repository of Mozart works, after the Bibliotheca Mozartiana in Salzburg, Austria – the classical composer’s birthplace. Most of its collection – including the manuscript for Don Giovanni – was contributed by the Conservatoire de Paris, though this newly-rediscovered notebook is thought to have been taken into the Library’s possession sometime after the Duke’s properties were seized in 1794, during the French Revolution.

More about Mozart’s notebook can be found here.