Requiem (Mozart)

The circumstances of the Requiem's commission fed a legend almost from the moment Mozart died. In the summer of 1791, while he was finishing The Magic Flute, an anonymous messenger arrived offering a generous fee, half in advance, for a Requiem Mass, on the strict condition that Mozart never learn or seek out who was actually paying for it. The commissioner was in fact Count Franz von Walsegg, an amateur musician with a habit of commissioning works from established composers and then passing them off as his own, who wanted a Mass to commemorate his wife's recent death and likely intended to claim authorship of it himself, as he reportedly did with other commissioned pieces.

Mozart, already unwell and increasingly convinced he was writing his own Requiem in a more literal sense, worked on the score between other commitments through the autumn before his health collapsed entirely in late November. He died on December 5, 1791, with the opening Requiem aeternam complete in full score but the following movements finished only in vocal lines and figured bass, and the Lacrimosa stopping after just eight bars, at what several scholars have noted is a peculiarly apt line of text to have been the last thing he set: "Lacrimosa dies illa," that tearful day.

Constanze Mozart, needing to deliver a complete score to collect the remainder of the commission fee, first approached Joseph Eybler, who completed some orchestration before abandoning the task, then turned to Mozart's student Franz Xaver Sussmayr, who finished the orchestration and composed the remaining movements largely from scratch, producing the score performed under Mozart's name ever since.

Because so much of the Requiem as normally performed was written or completed by someone other than Mozart, scholars have spent more than two centuries trying to separate his hand from Sussmayr's, work made harder by the loss of most of Mozart's working sketches for the later movements. What survives in Mozart's own hand with reasonable confidence is the Introit fully orchestrated, and vocal parts with figured bass for the Kyrie and most of the Sequence and Offertory; the Sanctus, Benedictus and Agnus Dei exist with no confirmed surviving Mozart material at all, raising the question of how much of their musical material, as opposed to just their orchestration, is actually Sussmayr's own invention.

Sussmayr himself later claimed in a letter that some of the material for these later sections came from verbal instructions or sketches Mozart had given him before dying, sketches that, if they ever existed in written form, have not survived to be checked. Modern scholars remain split on how much weight to give that claim, and on whether Sussmayr, a competent but by most accounts less gifted composer than Mozart, was capable of matching Mozart's style as closely as some passages suggest, or whether those passages preserve genuine (if now lost) Mozart material passed to him by other means.

Several later composers and musicologists, dissatisfied with aspects of Sussmayr's completion, have produced their own alternative completions since the late twentieth century, none of which has displaced Sussmayr's version as the standard concert text, a testament less to its unquestioned authenticity than to how thoroughly it has become the Requiem audiences expect to hear.