Before his death, Mozart had only written the first eight measures of the Lacrimosa, the last section of the Sequence in the Requiem. It is a commonly believed that these were the last notes Mozart ever wrote, but it is not certain. What is certain is that the Lacrimosa was not the last section that Mozart had drafted. Mozart wrote out the vocals and figured bass, and some orchestration, for the Offertory (Domine Jesu and Hostias) as well. Based on the evidence, it is virtually certain that Süssmayr’s exclusive authorship of certain sections in the Requiem does not begin until the Sanctus; yet, even that has been debated. In any case, why did Mozart have more music written for later sections (the Domine Jesu and Hostias) than he did for the Lacrimosa?
It is possible that Mozart, who liked to plan out the music in his head before writing it down (although the popular image of Mozart writing down an entire composition in his head is simply a myth), wasn’t yet certain about what he wanted to do. If he already had ideas for the Offertory, he could have skipped the Lacrimosa – temporarily, of course. This is not improbable, considering that composers are not obligated to write the sections of a mass, the movements of a concerto or symphony, etc, in the order in which they will be performed. Creative work cannot be forced, so musicians simply let their imaginations and inspirations guide them. This is the only scenario in which it is possible that the eight measures of the Lacrimosa were the last notes Mozart ever wrote. However, even if this is true, the popular image of Mozart dictating the Lacrimosa to Salieri or Süssmayr is simply a myth.
Others believe that the conclusing measures of the Hostias in the Offertory were Mozart’s last notes – certainly the thief who ripped the end of the manuscript at the 1958 World Fair thought so! If this is true, then there is only one conclusion: Mozart began the Lacrimosa, and then moved on to the Offertory because he wasn’t sure how to proceed. This is probable if we discard the notion that Mozart wrote down everything directly from what he had already completed in his head and never had to make drafts. Although most of Mozart’s sketches have been destroyed, it is certain that he did make drafts, which would have been especially necessary in fugal and contrapuntal writing.
Another draft discovered that appears to have been intended for the Lacrimosa is the “Amen” fugue sketch. Thus, the second theory – that Mozart began the Lacrimosa and then moved on to the Offertory – becomes more plausible. The existence of the sketch for the fugue (which will be explored in greater depth later on) shows that Mozart must have begun the beginning Lacrimosa, and then skipped to the end of the section. The reason for his temporarily setting aside the middle portion of this section may have been a textual issue. The end of the Dies irae Sequence contains the words, “Pie Jesu Domine, dona eis requiem. Amen.” The words “dona eis requiem” appear in the beginning of the Requiem (the Introit) and at the end (the Lux Aeterna). They appear only once elsewhere, in the Lacrimosa, in the middle of the Requiem. Naturally, Mozart, who often used word painting and other techniques to demonstrate the meaning of the words in the music, would have thought about the significance of the appearance of “dona eis requiem” in the middle of the entire Requiem. Thus, he probably would have wanted to put aside the Lacrimosa for further thought and move on the Offertory first.
It is virtually certain that the “Amen” fugue sketch, discovered by the musicologist Wolfgang Plath, was a draft for the Requiem. Drafts for Die Zauberflöte and more significantly, for the Rex Tremendae from the Requiem, were also on the same sheet of paper, proving that the sketch was from 1791.. There was just one word, “Amen,” so it was obviously sacred music. There were no clefs, so Plath placed, from the top down, soprano, alto, ten, and bass clefs. Then the music would only make sense if there was one flat in the key signature which meant that the music was in F major, but since the music was obviously in minor mode, judging from the presence of the raised sixths and sevenths, it had to be D minor. The only sacred music in D minor that Mozart wrote in the year 1791 was the Requiem, and the “Amen”, logically, was intended to end the Lacrimosa.
It is reasonable that Mozart would have wanted a fugue to conclude the Sequence; every other major liturgical section in the Requiem ends with a fugue: the Kyrie, Quam olim Abrahae, Osanna, and Cum sanctis tuis. However, the well-known Süssmayr completion does not contain an “Amen” fugue; instead, he wrote a plagal cadence. There are several different explanations: either Süssmayr did not see the sketch, did not know what the sketch was for, or ran out of time to complete the sketch since he was under pressure to complete the Requiem for Constanze Mozart to collect the payment. He had limited time to get the Requiem completed and delivered. Emanuel Schikaneder, the theater director at the Theater auf der Wieden who had written the libretto for Mozart’s Die Zauberflöte, had commissioned an opera from Süssmayr. In any case, there is nothing wrong with a plagal cadence
Musicologists and scholars often sound antagonistic when they mention that Süssmayr did not complete the “Amen” fugue sketch. While the lack of a fugue does, in a sense, disrupt the unity of the Requiem, it may be that Süssmayr was setting the end of the Sequence apart from the typical conclusions of the other liturgical sections. Perhaps he realized that he needed to emphasize the ending of the Lacrimosa because of the words “dona eis requiem.” He did that in two ways.
First, Süssmayr borrowed thematic material from the Introit / Lux Aeterna for the “dona eis requiem” section in the Lacrimosa. The music contains the original five-note “Requiem theme” found in the beginning of the Requiem itself, immediately following a retrograde of the same theme.
Süssmayr also used chromatic completion, a technique in which all twelve tones possible in Western music unfold throughout a piece of music. The twelfth tone arrives at a point in the music in which it emphasizes a structural aspect, or even the words (in this case, theological meaning). Sometimes there are many “cycles” of this kind of unfolding, and two movements of the same piece can be linked together. In the case of the Requiem, every section except the Lacrimosa ends on an incomplete cycle, and the missing tone(s) is found in the next section. The cycles at the beginning and the end are linked together, both missing an E-flat. However, the F# on the second syllable of “Amen” in Süssmayr’s plagal cadence completes a full cycle. I propose the theory that this was done intentionally to emphasize “dona eis requiem. Amen.”
Süssmayr’s decision to complete the last chromatic cycle in the Lacrimosa can also have other theological implications: “Sicut erat in principio, et nunc, et semper, et in saecula saeculorum” (“as it was in the beginning, is now, and ever shall be, world without end”). If the beginning is represented by the Introit and the end by the Lux Aeterna, the words “dona eis requiem” appearing in the Lacrimosa must be emphasized as the now. And the F# on the “Amen” – “so be it” – affirms this Catholic belief in eternal life. If the fact that the entire Requiem is linked together represents eternity (because the beginning and the end are connected), then this affirmation of belief in eternal life at the “Amen” is something worth thinking about.