Leonhardt, with his consort in Amsterdam, and Harnoncourt, with his Concentus Musicus of Vienna shared the task of recording, with an unmatched team of vocal and instrumental soloists, Bach's roughly 200 surviving "concerti sacri", perhaps a further hundred being lost to us. It was a repertoire more honoured in the history books than experienced in performance. This enterprise changed that state of affairs for ever.
The arguments which are now sometimes made (chiefly by those who are unaware of the extraordinary and revolutionary step which these performances represented), decrying the slightly "raw" (I prefer "vocal") sound of original instruments, or the occasional shakiness of a boy soprano soloist, miss the point of this enterprise, which was to present the music in a new way using Bach's own contemporary resources. Leonhardt and Harnoncourt are the first to insist that using "historical instruments" makes sense because those are simply the best tools for the job. Re-constituting something old has never been their aim. Rather, their idea was to break free of the mindless tradition of performance which took no account of the sounds that Bach actually had in his head when he created his "well-regulated" music for the churches of Saxony. And how does this work in practice? We are left to marvel at an extraordinary level of accomplishment on the part of nearly everyone associated with this project, vocally and instrumentally.
Gustav Leonhardt was well aware (and hopeful) that subsequent generations would likely improve upon aspects of performance which still remained to be sorted out. But, as he said, it was a start. Indeed, when he and Harnoncourt were jointly awarded the Erasmus prize in the Netherlands in 1980, he remarked, with singular modesty and self-awareness: "It was not done well, but it is remarkable that it was done at all". This tells us more about Leonhardt's famous humility, than it does about the standards of these performances, which are usually (with few exceptions) very high indeed. In many instances they will never be surpassed. What we have here is a glimpse of one of music's "golden" ages captured forever on disc. What the listener will marvel at is the extraordinary assuredness of technique and style which is evident in every one of these cantata performances.
The solo vocal contributions of Kurt Equiluz, Max van Egmond, Paul Esswood, Marjanne Kweksilber (BWV 51) are simply without equal, and the current generation of fine Bach singers would be the first to concede their enormous debt to the participants in this great enterprise (their teachers, in many cases). The choirs should also be singled out for attention: Wiener Sangerknaben, Tolzer Knabenchor, Hannover Knabenchor, Choir of Kings College, Cambridge as well as directors Heinz Hennig, Gerhard Schmidt-Gaden, Philippe Herreweghe, David Willcocks and Hans Gillesberger. So Europe's finest were all involved in this.
The instrumental soloists: Frans Bruggen, Walter van Hauwe, Kees Boeke, Anner Bylsma, Jurg Schaftlein, Lucy van Dael, Sigiswald, Wieland and Bart Kuijken, Ton Koopman, Bob van Asperen, Lidewij Schiefes, Alice Harnoncourt, Herbert and Herwig Tachezi, Erich Hobarth, Friedemann Immer - to list only the more familiar names - have created a whole world of intelligent and vital performance which has transformed musical thought in our time. No-one in any area of musical performance has remained untouched by the ideas which are so forcefully presented here (even those who'd be the last to admit it). The fundamental idea of treating each period's music as a vital and representative product of its time is one which now extends to music of all periods, signaling the fulfilment of one of Leonhardt's and Harnoncourt's chief aims: to eliminate the artificial distinction between mainstream and "early" music, and, instead, to treat all music with proper respect for its origins and context.
What this recording continues to offer the listener is the experience of hearing the music for the first time, which the technical polish of subsequent surveys cannot quite match. For the young person wishing to learn about music, there is no better starting point than investing in this set, now available at a fraction of its original cost (unfortunately, minus the scores, which were one of the hallmarks of this series in its first incarnation on LP.
It seems pointless to list highlights, but one might start with the following: BWV 1, 6, 8, 11, 13, 19, 23, 29 and so on. The list is endless. Better still, buy the set and begin a life-time's voyage of discovery instead. Bach, Leonhardt and Harnoncourt: you can't do better than that. Oh, and we should also acknowledge the contribution of the founder recording producer for this project, Wolf Erichson (even though he didn't stay with Teldec to the end of it). Without him, the revolution in informed and intelligent music performance on recordings would never have happened.