For the conductor Nikolaus Harnoncourt, Schubert`s two late Masses in A flat major D 678 and E flat major D 950 rank with Beethoven's Missa solemnis as the "greatest, most important and artistically significant attempts to come to terms with the Christian liturgy. I believe that the social situation and audiences' mental outlook, together with the whole way in which religion and life are bound up with each other in Central Europe, means that, for listeners and musicians alike, these works have an expressive force that is quite literally capable of stirring us to the very depths of our souls. I do not think that at church is the right place for us to attempt to confront their underlying meaning."
For his fiist public performances of these Masses within the framework of the tenth Styriarte, Harnoncourt chose the Stephaniensaal in Graz: having heard masses performed in the most varied venues, he is of the opinion that "the space itself is transformed by the pieces spiritual essence. This music is not an act of pious devotion but Schubert's impassioned attempt to come to terms with death." As proof of his claim that the composer was seeking to express a profoundly personal message, Harnoncourt cites not only the works themselves but also the fact that, without any outward prompting, Schubert spent almost three years of his life, from November 1819 to September 1822, working on the A flat major Mass.
Even the choice of A flat major as the Mass's principal key speaks volumes in this context. It is a key that is found only exceptionally in settings of the mass but one which, in the words of the German poet and writer on music, Christian Friedrich Daniel Schubart (1739-1791), expresses the ideas of "death, the grave, dissolution, the Last Judgement and eternity", suggesting a message that is progressively decoded in the course of the work's six rnovements, with their cyclically ordered sequence of tonalities. With the exception of the Sanctus, the movements are in a third-based relationship with one another: A flat - E (= F flat) - C - F - A flat - A flat. They thus form a self-contained whole, exploring the whole harmonic circle, at the centre of which is the idea of incarnation and Christ's crucifixion, for which Schubert modulates to A flat major in the Credo. This overall design reflects the composers meticulous but original approach to 19th-century notions of the symbolism of the different tonalities, one of the most astonishing consequences of which is the transition from the Kyrie to the Gloria, which is notated in E major - according to Schubsrt, the key of “noisy jubilation and joyous laughter" - but which is heard by the listener in the enharmonically respelt key of F flat major. The resultant ambivalence between the way in which the music is notated and the way in which it sounds is typical of so many passages in the A flat major Mass that it often seems as though Schubert were trying to coax from the music an answer to his questions, an answer which the rnusic, in all its complexity declines to reply to unequivocally.
The Kyrie ends with a question mark and thus fails to convey the usual sense of unquestioning trust. As a result of its combination and assimilation of motifs from the Kyrie and Christe, it is in five sections - two more than the ternary form traditionally associated with this movement's Trinitarian symbolism. This technique of symphonic development is one that we find repeatedly in the A flat major Mass, where - as in the “Gratias agimus" - it clearly serves to point up affinities between what is otherwise antithetical rnaterial. The important role of the orchestra in interpreting the text of the Kyrie becomes even more pronounced in later movements, especially in the Credo, where Schubert omits certain words from the vocal line and entrusts them, instead, to the orchestra as the voice of absolute music. In doing so, he not only harks back to the centuries-old tradition of antiphonal writing but, at the same time, reveals himself as far in advance of his age in propounding this concept of music as something absolute. For Nikolaus Harnoncourt, there is no basis whatsoever to the reproach, so often levelled at Schubert by writers on the subject, that his failure to set the words “Et in unam sanctam catholicam et apostolicam ecclesiam" in the Credo reveals an anti-eccleciastical bias and might therefore be taken to imply an anti-religious outlook on the composer's part: "Ever since they were first set to music, the words of the Gloria and Credo have been treated selectively. It is not true that Schubert did not set a particular phrase because he did not believe in it - that would be an entirely worthless and false interpretation. Even Bach and Haydn, whose loyalty to the church is not in doubt, omitted individual lines. I should like to warn listeners against reading too much into these works on the basis of what others have written about Schubert and believing that he wrote this or that piece only because he held this or that view, because he hated his father, because he was gay or goodness knows what else. I think that it is Schubert's authentic voice that we hear in these Masses. We should concentrate on the works themselves. Schubert speaks through his music, he speaks the language of music."
The suggestion that Schubert did not set certain passages of the mass for ideological reasons becomes completely untenable when we recall that, with the single exception of his first setting of the mass, he never included the words “Et exspecto resurrectionem”. Yet, if this central idea were not contained in the music, the rest of the phrase, "et vitam venturi saeculi. Amen", would be completely meaningless.
In this context the conductor draws attention to Schubert's setting of the cantata Lazarus, which distracted him for a time from his work on D 678. For Harnoncourt, it is by no means certain that Lazarus was left unfinished. "Everything suggests that this work - which Schubert wrote without a commission and which he did not discuss with his friends - was indeed completed. Rather, parts of it have gone nnssing only as a result of external circumstances - possibly due to negligence on the part of Schuhert’s heirs. That there is a connection between the two works rs clear, I believe, from the composer's use of tonality and from the spiritual attitude that they express." Schubert’s unconventional handling of many individual details and his often impassioned and, therefore, highly demanding musical language, in which his recourse to Baroque rhetorical gestures is combined with the boldest harmonic blocks, places the A flat major Mass squarely in the area where, in the words of Nikolaus Harnoncourt, all art belongs as a matter of course - "in the area of the mythical, on the cusp of the incomprehensible".