There have been a host of masterpieces in music history, to which over time, various stories have attached themselves, often making them more popular as a result. Sometimes, they even result in the work picking up a nickname. The majority of these have proven apocryphal, but one of the most extraordinary stories of all, the one surrounding Mozart’s Requiem, has, against the odds, turned out to be true.

In the last year of his life, Mozart was working feverishly on the Magic Flute. He was visited by a mysterious stranger who would not name himself and who commissioned a requiem mass from the composer. On a number of occasions, the man appeared dressed in black, to hurry Mozart along. At this time, Mozart was seriously ill. It makes the often stated assertion that Mozart felt he was writing his own Requiem all the more credible. Indeed, his illness proved fatal, and Mozart was unable to complete it. Even on his last day on earth, Mozart was still humming the work’s melodies.

After his death, Mozart’s most likeable pupil, Franz Xaver Süssmayr completed the score. Music scholars are still debating whether Süssmayr was working from sketches or else from his own imagination, when he produced the missing Sanctus, Benedictus and first part of the Agnus Dei. In any event, he produced a passable imitation of Mozart’s style, something that is a credit to his humility and also shows that a composer of middling abilities is able just occasionally to approach the level of a master. It transpired that the mysterious man in black was a shady aristocrat, Count Walsegg, who to maintain the fiction that he was himself a composer, was in the habit of making commissions from local composers (and of course, denying the true provenance of the works he paid them for). The first performance of the Requiem probably took place in the chapel of Walsegg’s mansion, which was performed as a requiem to his wife (composed by himself, naturally). Constanze, Mozart’s widow, soon made the work public under Mozart’s own name and ensured its publication.

Süssmayr was not the first person to attempt a completion. Originally, Mozart’s widow asked conductor Joseph Eybler to undertake the work, but he was unable to measure up to the task at hand. Modern scholars believe that a far larger part of the Requiem is original Mozart than was originally believed. The Requiem and Kyrie, most of the Dies irae, Tuba Mirum, Rex tremendae, Recordare, Confutatis, Domine Jesu and the first eight bars of the Lacrymosa survive in Mozart’s own hand. It would seem that Süssmayr composed only the central section of the Benedictus and the Hosanna, and perhaps the first half of the Agnus dei.

Mozart’s entire oeuvre is a kind of process of synthesis. In his work all the characteristics of German, Italian and French music unite. In the last period of his life, he added to this “spatial” synthesis a “temporal” one. In all these works, including the Magic Flute and above all the Requiem, he manages to integrate the baroque practise of independent voices and counterpoint with his own classical style built around melody and thematic contrasts. Needless to say, the end result is miraculously complete and beautiful.

The Requiem also gave Mozart room for exploring another kind of antithesis. Mozart was a profoundly dramatic composer, not just in his stage works but even in his most abstract instrumental pieces. His mature church music is largely theatre music without a stage, and this is also reflected in his treatment of the Latin text. Although he paid great respect to the liturgical demands and rules, the Requiem is as much music drama as church music. Just think of the depiction of the final judgement, or else the evocation of the happiness of the next world. This drama even plays itself out within individual movements. It is truly a masterly synthesis, and from its very first bars, with it questions of life and death, addresses people of all eras. For this reason, it is one of the great compositions of music and art.