Wolfgang Amadeus Mozart’s Mass in C minor (K. 427) stands alongside the Requiem (K. 626) as his most remarkable church composition. Today it enjoys almost cult status, first because of its monumentality, which is unique in Mozart’s sacred vocal music, and second because, like the Requiem, it partakes of the aura of the unfinished and mysterious. The exact circumstances that gave rise to it as a votive mass have eluded explanation to the present day. The same applies to the reasons why it was left unfinished and to many details of its first performance, which, as far as we know, took place at St. Peter’s Church, Salzburg, on October 26, 1783. Finally, the transmission of the original sources also raises many questions. Indeed, it is astonishing that the Mass, although left as a torso, was performed at all during Mozart’s final visit to Salzburg.
It seems that the work had not been commissioned but that it was written to fulfill a vow, which is vaguely discernable in the incomplete correspondence with this father, as he writes on January 4, 1783 in response to his father’s reproaches:
“It is quite true about my moral obligation and indeed I let the word flow from my pen on purpose. I made the promise in my heart of hearts and hope to be able to keep it. When I made it, my wife was not yet married; yet, as I was absolutely determined to marry her after her recovery, it was easy for me to make it — but, as you yourself are aware, time and other circumstances made our journey impossible. The score of half of a mass, which is still lying here waiting to be finished, is the best proof that I really made the promise.”
The mention of the Mass in this context makes clear that the work did not, as is occasionally presumed, owe its existence to an external incentive, such as the 1,200th anniversary of the Bishopric of Salzburg, officially celebrated in 1782.
By all appearances, his wife, Constanze’s, participation was an indispensable part of Mozart’s vow, and in fact this may have been one reason that the first performance of the Mass took place at St. Peter’s, rather than the Salzburg Cathedral, since in the eighteenth century, women were still not allowed to partake in musical performances for church worship. Indeed, the delicate and deeply moving soprano solos of the “Christe eleison” in the “Kyrie” and, perhaps most famously, the “Et incarnatus est” in the “Credo” (called “matchless” by Pope Francis, who proclaimed in an August 2013 interview that the aria “lifts you to God!”) are widely considered as love offerings by the composer to his soprano wife.
Just as we must forever wonder about the voice that inspired Mozart to write such sublime music, we must also forever wonder how Mozart would have completed the Mass, for the work has come down to us in fragments. Moreover, not only were some sections of the Ordinary Mass left unset, with others only left in advanced drafts, even some of the sections that Mozart finished have come down to us incomplete.
Bärenreiter, working together with the International Mozarteum Foundation Foundation in Salzburg, has published a new edition of this work, reflecting the cutting edge of scholarship while doing justice to the needs of performers. This new edition completes and reconstructs movements according to high scholarly standards in order to come as close as possible to the work itself:
- The “Kyrie” and “Gloria,” both of which survive complete in Mozart’s hand, are presented in a scholarly-critical Urtext edition.
- The first two sections of the “Credo” have been meticulously completed by the editor, Ulrich Leisinger, drawing on original Mozart compositions, e.g. the aria “Deh vieni non tardar” from The Marriage of Figaro, and paying attention to a stylistically appropriate and transparent sound.
- The “Sanctus” and “Benedictus” (with the “Hosanna”), which are either incomplete or survive only in secondary sources, have been reconstructed by the editor.
- On the use of trumpets and timpani in “Credo in unum Deum”: “To omit trumpets and timpani at the opening of the Credo, appropriately set in C major, is to contradict eighteenth-century church music practice.”
- On the use of trombones in “Credo in unum Deum” when no wind score came down to us: “As with the Sanctus, Mozart probably would have entered the trombones [in the wind score], for he normally did not have them play continuously ‘colla parte’ with the lower voices.”
- On the absence of horns in “Et incarnatus est”: “The Figaro aria ‘Deh vieni non tardar’ K. 492 (1786) in particular reveals such striking parallels in its handling of the instruments that the expansion of the orchestration to include two horns, as is found in other reconstructions, has little justification. As in other scores, when Mozart prepared his staves, he entered systems which he did not necessarily make use of when he later filled in the instrumentation.”
- On the reconstruction of the “Hosanna” fugue for double choir: “Of special significance is the observation that Mozart’s Salzburg church compositions for double choir invariably have the three trombones playing ‘colla voce’ together with choir I.”
Reconstructed and added parts are rendered in small print. Sections without any known sources are left out in this edition. Rounding off the publication are an extensive Foreword (Ger/Eng) and a detailed Critical Commentary (Eng).
The premiere of Ulrich Leisinger’s new edition was given in April 2019 in the Elbphilharmonie Hamburg by the Hamburg State Philharmonic Orchestra and the ChorWerk Ruhr under the baton of Kent Nagano. The first Austrian performance took place in Salzburg in August 2019 in the Great Hall of the Mozarteum, with Andrew Manze conducting the Salzburg Camerata to rousing applause from audience and critics alike.