Boismortier’s Six Sonates a deux violons Op. 71 were published in 1738, but it can be assumed that few copies were printed; all recent catalogues of Boismortier’s compositions describe Op. 71 as being ‘lost’. In actual fact, at least one copy has survived; it was deposited at the Bibliothèque municipale de Lyon in 1981, some 243 years after its publication, even though its location has evidently remained unknown to scholars until now. The full title of Op. 71 — Six Sonates à deux violons, dont...