Who wrote Mozart’s Requiem?

Mozart’s last composition, his Requiem Mass K.626, is not just celebrated for being a work of profound genius, it is also forms the centre-piece of one of music’s greatest mysteries. Commissioned by the dark emissary of an anonymous figure, Mozart died before he could complete it. Miraculously, after his death the finished work, apparently entirely by Mozart, was presented to the public. Involving an eccentric count, a suspected murder and a deceitful wife, the story of how this was achieved is very strange indeed...

What is a Requiem?

A Requiem or Requiem Mass is a musical setting of the Roman Catholic rite normally celebrated at a funeral. In Mozart’s setting it divides the texts into the following movements:

I: Introit (Requiem Aeternam)
II: Kyrie Eleison
III: Sequence:
i) Dies Irae
ii) Tuba Mirum
iii) Rex Tremendae
iv) Recordare
v) Confutatis Maledictus
vi) Lacrimosa
IV: Offertorio:
i) Domine Jesu
ii) Hostias
V: Sanctus:
i) Sanctus
ii) Benedictus
VI: Agnus Dei
VII: Communio:
i) Lux Aeterna

The Amadeus Perspective

In one of the most memorable scenes the 1984’s Miloš Forman movie ‘Amadeus’ we see Mozart’s rival and enemy, Antonio Salieri, at the composer’s bedside transcribing passages of the work from the dying Mozart. Unbeknownst to Mozart, it is Salieri who has commissioned the work, who plans to pass it off as his own after murdering the composer:

Before the work is complete, however, Mozart, inconveniently for Salieri, dies.

The Truth

The story only contains elements of truth. The work was actually commissioned by a certain Count Franz von Walsegg, an eccentric nobleman who was in the habit of passing off composers’ works as his own. Whilst there was no deathbed scene involving Salieri, Mozart did become ill during the work’s composition and may have given instructions as to how it might be completed in the event of his death. That the work was left unfinished is beyond a doubt, despite subsequent attempts by Mozart’s wife Constanza to hide this fact.

As for Salieri, he did not murder Mozart, though there were rumours in Vienna after Mozart’s death that he had been poisoned by him. This contributed to Salieri’s later mental breakdowns and eventual committal to an asylum.

What did Mozart leave after his death?

Out of the whole work only the first two movements, ‘Introitus: Requiem aeternam’ and the Kyrie Eleison were completed entirely by Mozart. After this the Dies Irae, Tuba Mirum, Rex Tremendae, Recordare, Confutatis, Domine Jesu and Hostias choral and vocal solo parts were complete along with most of the orchestral bass line and some figures from elsewhere in the orchestra (for example the Dies Irae violin 1 line is by Mozart).

Of the Lacrimosa, only the first eight bars were written. The Sanctus, Benedictus, Agnus Dei and Lux Aeterna were all missing.

Attempts to complete the work

In need of the commission fee from Count Walsegg, Mozart’s wife Constanze first asked the composer Joseph von Eybler to complete the work. In many ways he was the ideal choice, being respected by Mozart and having been close to him up to his death. Eybler was able to make some progress in the movements missing their orchestration but eventually felt unable to continue, possibly because of the respect he felt for his dead friend.

Constanza then turned to composer Franz Xaver Süssmayer. Süssmayer incorporated some of Eybler’s work in his own orchestration and then composed the missing Sanctus, Benedictus and Agnus Dei himself. The Lux Aeterna reuses part of Mozart’s own Introitus and the whole of the Kyrie Eleison.

Constanza’s deception

The completed work was handed to Count Walsegg, the whole being passed off as being entirely by Mozart, allowing Constanza to collect the remaining commission fee. She continued to claim the work was entirely by her husband, helping this version to gain the acceptance which it still enjoys today.

This is despite the fact that, as musicologists such as Richard Maunder have pointed out, Süssmayer’s completion is riddled with errors of musical grammar and the completed movements are of noticeably poorer quality than those completed by Mozart (the rather perfunctory Sanctus, especially, is a good example of this).

Later attempts at completion

Given the sometimes poor quality of Süssmayer’s work, there have been many later attempts to complete the Requiem or at least to clean up Süssmayer’s errors. The most extreme is Richard Maunder, who removes the Sanctus and Benedictus entirely, providing no replacement. He retains the Agnus Dei, suspecting that Mozart had a hand in it, recomposes the Lacrimosa after the first bars and adds a final Amen based on a sketch that was discovered after Süssmayer.

There have been many other completions, none of which, however, has gained the traction of that of Süssmayer. This is perhaps right and proper— Süssmayer was on the scene immediately after the composer’s death, had access to Mozart’s manuscript and to advice from Constanza and Eybler. It is therefore likely as close as we can get to a faithful complete version of Mozart’s last composition, one which, despite Süssmayer’s problematic contribution, remains a work of great genius.