After Mozart’s death, Constanze, his widow, asked Joseph Eybler to complete Mozart’s unfinished requiem. Although Eybler soon gave up the completion, Franz Xaver Süssmayr eventually took charge of the entire completion. While orchestrating the Sequence, Süssmayr borrowed Eybler’s ideas and also incorporated some of his own. However, Eybler gave up after writing two rather unconvincing measures in the soprano line in the Lacrimosa, so Süssmayr completed the rest. How are Eybler’s and Süssmayr’s orchestration similar and different from each other?
In the Dies Irae, Eybler uses the wind instruments in the orchestra to reinforce the choir and make it sound more vivid. He does this to continue the “block-like rhythm” of the choir as an echo. Trumpets and timpani are more subtly used than in Süssmayr’s completion.
Süssmayr lets the basset horns run with the choir, for some reason always avoiding the note “g,” while Eybler employs them as sounds in their own right (the first time he does this is in measures 10-19 in the Dies Irae). Eybler continued Mozart’s strings throughout the entire section and wrote out the woodwinds, trumpets, and timpani in a similar manner. Eybler also makes use of a dotted rhythm in the Dies Irae, while Süssmayr does not.
For the Tuba Mirum, Eybler did not write anything in the two staves that Mozart had left blank above the trombone solo part. This movement shows how the filling out of the remaining instruments (particularly the strings) is determined by the instrumental bass. Some examples include the off-beat quarter notes in bars 5-17, the throbbing eighth notes in the tenor solo part, and the off-beat eighth notes starting from the 29th measure. Many have commented on how these rhythms correspond with the Latin text; indeed, another way of completing this movement cannot be imagined.
Following after Mozart’s example, Eybler uses divisi violas, while Süssmayr does not. Eybler did not write woodwinds in the Tuba Mirum for the solo quartet. They, along with the trumpets and timpani, are not used again until the Confutatis.
It is regrettable that Eybler did not use trumpet and timpani in the Rex Tremendae, which reduces the dramatic effect that this movement calls for. In this movement and in the Recordare, Eybler does not add anything in the staves left blank by Mozart.
Süssmayr adopted Eybler’s completion of the strings in the Rex Tremendae, with small changes made. While Eybler used chords in the second violin part to support the choir, Süssmayr used woodwinds for the same function and underlined the rhythm of the strings with trumpets and timpani.
Unlike in the Rex Tremendae, Süssmayr did not use Eybler’s ideas in the string instruments for the Recordare. Eybler lets the viola run with the bass line, while Süssmayr uses them to support the vocals.
However, sometimes Süssmayr does borrow Eybler’s ideas in this section, for instance at the “Quarens me” and the “Imgemisco.” In measures 46-49 (“Tantus labor”), the accompanying figure that Eybler had written, based on the main motif of the Recordare and placed in the first violin part, was used by Süssmayr in his second violin part. Süssmayr wrote, in the first violin part, an independent accompanying figure of his own.
Eybler’s orchestration in the Confutatis is very different from Süssmayr’s. Eybler places the woodwind chords above the unison of the strings, having its counterpart in the Organ (in the first printed edition). Unlike Süssmayr, he has no figures in the bass until the 26th measure. In accordance with this, the organ should play tasto solo up to this point.
This section also shows a difference in Eybler’s and Süssmayr’s uses of trumpets and timpani. Eybler uses them to intensify the movement: he uses off-beat quarter notes in the first passage and fanfare blasts in the second. Süssmayr uses the same fanfare blasts on the first and third quarter-notes in the measure.
Eybler wrote out the woodwinds by continuing Mozart’s notation directly in measures 26-29 and lets the instruments run exactly with the choir. They play and rest whenever the choir sings and rests. There was no other choice than to proceed in this direction, considering that these are the only indications for the woodwinds in the Confutatis. Süssmayr changes this by having the woodwinds enter one bar earlier with the A minor triad and continue to play until the end of the movement.
This problem also occurs in the organ part in the Confutatis. Mozart’s 25th measure has no figures, but also no tasto solo. An organist of the classical period would have know that a bass note without a figure, without any other indications, implies that a triad is to be played. In the 25th measure, a minor chord must be played, and would have been indicated with a natural accidental. An experienced organist would have known that only a minor chord could be played here.
Since nothing is marked, we can assume tasto solo; however, all the other measures with similar violin figures have figures. Figures are necessary because of the chromatic harmonies. Mozart’s indications show that the organ should only enter with the choir, but Süssmayr changed this by having the woodwinds and trombones enter earlier, in measure 25. This change was also made in the organ part, and in the first printed edition of the requiem shows the figures 3-5-8.
Many scholars have claimed that Eybler’s orchestration is better than Süssmayr’s, but this is merely an opinion, not a fact. However, it is interesting to compare their orchestration; even though Mozart had left what the two composers needed (vocals and figured bass, and some orchestral indications), Süssmayr and Eybler proceeded differently.
This also proves a different, but related, point. The arguments about Süssmayr’s eventual completion of the Requiem being un-Mozartian is completely invalid. No composer can exactly imitate another composer’s style, no matter how closely acquainted they might be. Therefore, it is time, as musicologist Simon Keefe said, to allow Süssmayr the right to his own aesthetic vision of the Requiem as a whole.