About this Piece

"It is quite true about my moral obligation... I made the promise and hope to be able to keep it," Wolfgang Mozart wrote to his father on January 4, 1783. "When I made it," the letter continues, "my wife was still single; yet as I was determined to marry her soon after her recovery [the fragile Constanze, it might be noted, outlived her husband by 46 years] 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 a mass which is still lying here waiting to be finished, is the best proof that I really made the promise..."

The "journey" referred to is almost certainly one from Vienna, where Wolfgang had moved in 1781, to his native Salzburg. The "promise" was to write a major work for Salzburg, the "half a mass," then, being the present gigantic torso. It is likely that the trip to Salzburg, which turned into a three-month-long sojourn, was also made for the purpose of introducing Constanze - whom he had married in August of 1782 - to his father, who had been displeased that his son had chosen a bride without his approval.

The letter contains the only reference Mozart himself ever made to K. 427, which was probably begun in July of 1782, after the finishing touches had been put to The Abduction from the Seraglio (the making of Mozart's reputation in Vienna as a composer for the stage) and sporadically worked on it the summer of '83. In the latter year he also produced the "Haffner" Symphony, K. 385, and a trio of piano concertos (K. 413, 414, and 415), and the first two of his string quartets dedicated to Haydn.

Sophisticated, sparkling wit, unbounded joie de vivre - all that worldly, happy stuff - characterize these compositions. And in their midst, towering above them, is this often dark, otherworldly giant.

The Mass was performed in its "entirety," which is to say that Mozart must have borrowed from other works to make it complete and suitable for liturgical performance, on October 23, 1783, in the composer's presence - he may have presided at the organ. The venue was St. Peter's Church in Salzburg, where its annual performance as part of the Salzburg Festival remains a tradition to this day. It is likely that Constanze sang the high-lying first soprano part.

The Mass in C minor works, even if not as a work for the sacred service, as the composer left it. Why he left it, however, remains a matter of conjecture. Time for its completion seems to have been available in 1782, but perhaps not enough to satisfy the gigantic demands made to match what had already been written. Later, other projects simply took precedence - added to the fact that Mozart's gifts as a composer of choral music were decreasingly in demand as the Vienna years progressed.

Still the music did see the light of day after that Salzburg premiere when, in 1785 the composer - in a bit of crossover magic worthy of a Bach or Handel (names not lightly dropped in this connection) - took the music of the Kyrie and Gloria, added a couple of arias and, presto!, the Italian cantata Davide penitente, K. 469.

But there is yet another seeming mystery regarding the Mass in C minor, only partially explained by the letter quoted above and the conclusions to be drawn from it: Why he wrote the Mass in the first place; why, freed from the tyranny of his employment at the Salzburg court and relocated to Vienna, where church music was not in demand (at least not of him), should Mozart have set himself such a task? He could readily have written something with greater practical application as an act of thanksgiving for Constanze's "recovery."

The most logical explanation - supported to a considerable extent by the score itself - is the great discovery that Mozart made just before he started on this work: the music of the late-Baroque, most importantly that of Johann Sebastian Bach and Handel, which had until then been generally regarded as hopelessly dated. It was a discovery that forced Mozart to re-examine his values as a composer, to question - and this, again, is conjectural - whether moving backward, to embrace major stylistic ingredients of the age of Bach and Handel, didn't in fact indicate a sort of progress.

The notion of the music of the past feeding the present and future was by no means a common one at the time. Constant novelty was demanded by audiences then, with Vienna's being the most fickle audience of all. The only music heard in the city's fashionable salons was contemporary music. A living composer, especially one who, like Mozart, was a celebrated performer as well (in his case on the piano) could conceivably revive one of his hits of preceding seasons on occasion. But as for a repertoire to draw on, as we have and demand today, forget it.

If indeed Mozart suffered a Baroque-induced crisis, he cured himself of its depressive effects with a series of compositions - the solo piano Fantasia and Fugue, K. 394, the two-piano Fugue, K. 426, transcriptions for string trio from Bach's Well-Tempered Clavier, and, most tellingly, portions of this Mass, with the Bach influence climaxing in the overwhelming double chorus of "Qui tollis" and the double fugue of "Cum Sancto Spiritu."

To sum up, what Mozart did write for the C-minor Mass was the Kyrie, Gloria, Credo (through "Et incarnatus est"), Sanctus, and Benedictus. For "Et incarnatus est," Mozart notated the vocal lines, the obbligatos for flute, oboe, and bassoon, and the bass, with the string parts having to be filled in by later editors. "The "Osanna" lacks the customary second chorus, so that has had to be completed via clues provided by the orchestra parts.

The reconstruction of this tremendous creation did not begin until early in the 20th century, instigated by the efforts of the German musicologist Alois Schmitt. His pioneering edition has since been superseded, most significantly by that used for the present performances, which is by the American scholar H. C. Robbins Landon and based on, in addition to Schmitt's pioneering work, further evidence of Mozart's composing and performing practices that has only lately come to light.

– Herbert Glass