Mozart’s Requiem, the last piece he ever worked on, has a trombone solo in the Tuba mirum movement. So far as I know, there is nothing like it anywhere in the standard sacred music repertoire. The important word in that sentence is “standard.”
People who wrote about musical performances in the nineteenth century were all too aware of the uniqueness of that solo. Throughout the century in every country from which I have seen magazine or newspaper articles, critics rarely mentioned the trombones in classical music except to complain that they were too loud. Along with more than one author of music books, they declared that a trombone solo was one of Mozart’s innovations they were glad no one else picked up.
What made them so sure it was an innovation?
They knew nothing of the generations of Austrian church music before Mozart and Haydn. That music had made no impact internationally when it was new. Although nineteenth-century audiences appreciated Mozart’s mature masterpieces, they showed little interest in the music of his youth and childhood. Mozart himself seems to have been little interested in sacred music after he left Salzburg.
Mozart’s Waisenhauskirche Mass
In 1768, a new orphanage church was dedicated in Vienna. Twelve-year-old Mozart of Salzburg composed the dedicatory mass. (Waisenhaus is German for orphanage; Kirche is German for church, so the name means orphanage church mass in English.)
A person of any age writing his first example of any genre will not stray very far from tradition. Tradition, in fact, provides the necessary models. In idiom, the Waisenhauskirche Mass is a so-called “cantata mass,” a form developed by Italian composers whose style dominated Austrian church music.
In a cantata mass, the text of the five movements of the mass ordinary is broken up into small chunks. Successive bits of text display different kinds of compositional structure: choral movements in strict counterpoint; other choral movements in a more declamatory, homophonic style with most of the melodic and contrapuntal interest in the orchestra; and solo numbers in a style familiar and well-loved from contemporary operas.
Likewise, the orchestration of the Waisenhauskirche Mass differs little from that of any typical mass of the time. Strings formed the backbone of the orchestra. Whatever winds Austrian composers selected to join the strings, they routinely used trombones to double the choral parts.
Solo instruments often joined vocal soloists. Second only to the violin, the trombone was the most common of these. Having the trombones play brief passages independent of the chorus must have also been fairly routine, because that’s what Mozart did in his very first mass composition.
Some regional differences are detectable. Vienna and Salzburg must have had a different pitch standard. Whatever they defined as the note A must have been about half a step apart. Everything written in Salzburg with a soloistic trombone part is in a sharp key. In Vienna it’s all in flat keys. In Salzburg, trombones doubled the alto, tenor, and bass lines in the chorus. Viennese composers used only two trombones, preferring to double the basses with a bassoon.
Young Mozart shows his awareness of Viennese pitch by his choice of C minor, with three flats, for the key. He uses three trombones for the independent parts, but supplied no bass trombone line for doubling the chorus. It seems odd to require a third trombone for just a few measures, though. Modern performances, at least use all three trombones to double the singers.
Aside from whatever he thought about composing his first mass, Mozart had no particular reason to value the piece. It was an occasional piece, more festive than what would be suitable for an ordinary mass in church. Touches that made it appropriate for performance in Vienna would have likewise been out of place back in Salzburg.
Mozart’s other sacred music
After he left Salzburg, he never completed another sacred piece in his life. His best known sacred work, besides the Requiem, is his reorchestration of Handel’s Messiah. He started one mass and completed four of the five sections, and then lost interest. He started the Requiem, but of course died before completing it.
All three of these pieces require three trombones. Mozart must have considered trombones a necessary part of a sacred orchestra. Although the question of how much of the orchestration of the Requiem Mozart complete himself is to complex to try to describe here, the infamous solo is not the way he used trombones for something more independent than mere doubling.
The vogue for trombone solos in Austrian sacred music peaked in about 1770. By 1780, for various reasons including the Emperor’s reforms of church music, there were not enough new trombone solos or enough opportunity to perform old ones to maintain the standard of technique needed to play them. Accordingly, Mozart’s solo is much more dignified and less florid than most that came before.
Why, late in his life and after the vogue had passed, did he decide to write a trombone solo? I have no idea, but unlike nineteenth-century commentators, I’m glad he did.
Illustrations are public domain, the photo of the church from Wikimedia Commons and the paintings from Music with Ease