Mozart was alone among his contemporaries in his ability to grasp the lessons of Handel and Bach: even Haydn’s encounter with the Handelian oratorio in London a decade later would provoke a dramatically different response. Mozart became entranced by their music shortly after his move to Vienna at “academies” held at the residence of the imperial librarian, Gottfried van Swieten, and began to absorb Baroque textures and techniques into the most up-to-date Classical forms of which he was master. The C minor Mass is by some distance his contrapuntal masterpiece and, had he finished it, would have been his first public demonstration of this rapprochement between styles. It pulls together the Bachian fugue of the “Cum Sancto Spiritu”, the Handelian “scourging” chorus of the “Qui tollis”, the galant concerto style of the “Laudamus te” and the purely operatic – the “Christe eleison”, based on a solfeggio composed for Constanze, and the “Et incarnatus est”, the prototype for Susanna’s Garden aria in Figaro’s last act.

This mixture of styles made the C minor Mass an ideal work during the digital boom-time of the 1980s for period-instrument ensembles, well-versed in the Baroque, to make an early foray into the music of the later 18th century. The reference versions by Gardiner (1986) and Hogwood (1988) listed above find contrasting ways to complete the half-finished sections of the work; Christophers opts for the completion by Helmut Eder also adopted (with some caveats) by Emmanuel Krivine. The Kyrie and Gloria are complete in Mozart’s hand (and indeed were co-opted by him for use in the oratorio Davide penitente, for which words were contrived, possibly by Lorenzo da Ponte, and shoehorned into the music of the Mass). Problems arise in the Credo, only two movements of which exist. Eder’s string parts for the “Incarnatus” over-egg this divine pudding while his decision not to add trumpets to the C major “Credo in unum Deum” robs the movement of the grandeur it surely deserves but also fails to make explicit its similarity to the opening of Handel’s Dettingen Te Deum.

The mixed voices of Boston’s Handel and Haydn Society are fully equal to Mozart’s florid choral writing if not quite matching the Monteverdi Choir for rhythmic incisiveness and tonal heft. As regards the soloists, the onus falls mostly on the two women, well matched in the “Domine Deus” and “Quoniam”; Gillian Keith is touching in the “Christe” if a little harried in the “Incarnatus”, while Tove Dahlberg admits only the slightest scoop in the wide leaps of the “Laudamus”. The two men wait patiently before combining effectively with the women in the “Quoniam” (tenor) and “Benedictus” (tenor and bass). This disc is more than simply a souvenir of an occasion audibly enjoyed by the good burghers of Boston. It offers a snapshot of America’s oldest concert-giving ensemble – still in rude health at the age of 195 – but also presents a commanding and compelling reading of an important if often overlooked monument in Mozart’s musical development