Mozart’s Requiem offers music history one of its most convoluted mysteries, the twisted threads of which are to this day the subject of further investigation. The tale begins as one of fiction would: A messenger arrives on Mozart’s doorstep with a commission for a Requiem Mass from an anonymous master. Would Mozart compose such a work, and if so, at what price? Mozart accepted, a fee was agreed upon, and a condition set that he not try to learn the identity of the commissioner. Although ill and fearful, Mozart began the work, but as he did, he became progressively more fatalistic, even believing that he was being given slow poison. According to the diaries of an English couple, Vincent and Mary Novello, who were in Vienna during this period, Mozart was certain the poison was being administered by the one who had commissioned the composition, and that “he had calculated the precise time of my death... it is for myself I am writing this.” In the same oppressive mental state, he said to a friend, “I am writing my own funeral music. I must not leave it unfinished.”
Tragically correct in the former statement, he ironically could not fulfill the latter, for he was destined not to complete the Requiem. It is possible that he might have, had he not taken time off to compose La clemenza di Tito for the coronation of Emperor Leopold in Prague on September 6, to write a Masonic Ode, completed on November 15, and (thank heaven) to finish Die Zauberflöte. By November, with his days numbered and anguished beyond belief, he was working on the Requiem from his deathbed, with his pupil Franz Xaver Süssmayr in attendance. When Mozart died on December 5, only the first two sections, the Requiem and the Kyrie, were completely finished; the second to the ninth movements — the Dies Irae to the Hostias — were left in draft form.
How, then, do we have a complete Mozart Requiem? Anxious not to lose the fee for the work, Constanze, Mozart’s widow, entrusted the completion of the score to Süssmayr and, in her confused and overwrought state, also to two of her husband’s other students, principally Joseph Eybler, but also Franz Freystadtler. When the Requiem was completed, the identity of the commissioner became known: he was Count Franz von Walsegg, who frequently paid composers for pieces which he then passed off as his own. He had intended for the Requiem to be performed in memory of his wife, who had died the previous February.
According to the most recent of the scholarly conclusions regarding the Requiem, Freystadtler’s role was small, in that he, together with Süssmayr, assisted with the completion of the fugue of the Kyrie. It remained for Eybler and Süssmayr to reconstruct and/or fill in the sketches — according to Mozart’s instructions or verbal intentions — of a large portion of the torso, and for Süssmayr to compose the Sanctus, Benedictus, and Agnus Dei. Many have been the arguments against the sections composed entirely by Süssmayr and even of those parts reconstructed by him. One is left with the sense, however, that Süssmayr is more to be thanked for saving the work from oblivion than censured for possibly taking more credit than is due him.
As an entity, the Requiem is a grandiose work, powerful in the fearsomeness of its visions of the Last Judgment, sublime in the gentleness of its evocation of salvation and eternal rest. Appropriately, the scoring is dark in color: lighter-hued flutes and oboes are omitted and the strings are often used in their lower registers. Yet, for all its solemnity, Mozart’s Requiem is a luminous and wondrous thing, more than merely beautiful.
— Orrin Howard