When this version of the B minor Mass appeared in 1968, it created something of a stir since it was the first recording on period instruments of a work that was still a sacred cow amongst 'mainstream' conductors. This account challenged established preconceptions on every performance practice issue one would care to mention. 'Authenticity' as a cult was yet to sow its seed of doubt on intuitive musicianship but, thankfully, not before Nikolaus Harnoncourt and others had unselfconsciously expressed their passion for baroque music in what Teldec's Das Alte Werk series reminds us was a golden age of historically-aware performance. If this recording was considered as little more than a slightly perverse curiosity in 1968, we can observe in retrospect, how sane and satisfying it is. In matters of finesse, time certainly has its say: the sheer virtuosity required in the concerted movements, such as the ''Cum Sanctu Spiritu'' and the ''Hosanna'', reveals that Harnoncourt was making significant demands on his singers and players. The chorus is an inconsistent animal, soft-centred in the opening Kyrie, especially the men who seem reticent alongside the bold and fearless Vienna Boys' Choir. Indeed the upper voices are what give the larger movements such a distinctive flavour shimmering and open throated trebles and the rich grainy sound of boy altos making their mark at almost every turn, especially in the ''Gratias agimus'', which is sensationally constructed by Harnoncourt (as too is the identical movement in No. 29 in the complete cantatas).
One of the main attributes here is that timbre and articulation had yet to become 'regulated' in a fashion perpetrated so eagerly in the 1980s. This is perhaps most evident in the arias, some of which are performed with supreme tenderness elasticity of phrasing and a sweet spontaneity of vocal colouring, ''Domine Deus'' may not be flawlessly sung but the dialogue between Rotraud Hansmann and Kurt Equiluz, and the intimacy of the accompaniment, results in a particularly moving utterance, as does ''Et in unum deum'', which breathes as naturally as any I know. Harnoncourt's booklet essay, old-fashioned in its didactic if unselfjustifying tone, still conveys a common sense which is admirably reflected in the graciousness of Helen Watts's ''Qui sedes'' and the absence of point-making which given the novelty of the circumstances would have been understandable. But instead, Harnoncourt never loses sight of the music and its spiritual dimension (the Credo is particularly luminous), never resorting to an over-emphasis of the pulse which can make the dance-inspired movements sound contrived.
So, apart from its importance as a document of its age, this is a version which still has much to say to us now. It has little of the sheen and polish of present-day recordings but a raw commitment and lithe pioneering spirit which is often intoxicating. Warts and all it grows on you too, which is recommendation enough it would seem, even if it is tempered by the 'high tech' expectations of Gardiner, Hickox, Christophers and the like. Excellent transfer sound despite an odd fade-out at the final cadence of ''Et in terra pax''.'