It is always a thrill to hear a performance of newly discovered music by a favourite composer, especially when it includes previously unknown versions of much loved works like Marin Marais’ La Folie variations. The music on this disc is a selection taken from a manuscript in the Scottish National Library of 150 pieces for solo viola da gamba.

We are informed by Jonathan Dunford that a) it belonged to an aristocratic viol player from Edinburgh, Henry Maule, who spent time in Paris in the 1670s; b) there is evidence to suggest that he acquired the manuscript from Marais before 1685; c) it contains 45 works unique to the manuscript; and d) the remaining works appear in Marais’ first three published collections of 1686, 1701 and 1711.

Marais (1656-1728) and Maule (d1734) were pupils of Sainte-Colombe in the 1670s. When Marais published his first collection, it, too, was without a continuo part, although shortly thereafter, in 1689, he was compelled to issue one separately. Accordingly, Dunford and his colleagues have extrapolated their own continuo accompaniment for the unique works.

It is fascinating to have evidence that Marais composed so much and so well as a young man, and it emphasises the fact that a great deal of music of this period existed either only in manuscript, or circulated – often for many years – before its publication.

But it is important to realise, as one listens to this CD, that much of what one is hearing is in fact being supplied by the performers: the hypothetical suites they have compiled, the continuo lines they have devised, along with the orchestration – if you will – of the continuo. Taking their cue from Marais’ suggestions, which preface the 1711 collection, the musicians have arranged three pieces for other instruments: the Prélude on track 2 is played on the theorbo alone as well as with bass viol on track 10; the Petit Prélude on track 3 is arranged for two bass viols in homage to Sainte-Colombe; and harpsichordist Stéphane Fuget plays the Chaconne on track 9.

The 12 further Folie variations (the published version appeared in 1701) are thrillingly played on this disc – interleaved, presumably, as they appear in the manuscript. The Spanish origin of the tune is underscored by Perrot’s colourfully idiomatic Baroque guitar accompaniments. Some of the viol ornamentation as realised by Dunford is unique to the repertoire, raising interesting questions about why Marais never published these particular variations or repeated these often astonishing effects in other works.

Elsewhere, the experienced Maraisian will be equally surprised by new twists and turns – rhythmic and melodic as well as harmonic – which don’t resonate with his better known published works. For the wary among us, reassurance will eventually come with the publication of a facsimile.

Dunford and his wife, Sylvia Abramowicz, have tremendous empathy with Marais’ music. They bring poise, virtuosity and verve to it as required. But to compete with the best Marais interpreters, Dunford needs to allow his long phrases more breathing space, and his trills to unravel more effortlessly. Both Perrot and Fuget accompany stylishly, although occasionally, in the variations and elsewhere when all four musicians are playing, there is simply too much going on; I think the evidence is clear that Marais preferred clean textures, too.

For me, the most beautiful item on the disc is the ravishing A minor Sarabande on track 6, with the Plainte on track 16 a close second.