Working on a Mozart horn concerto for the first time is practically a rite of passage. Mozart is a ticket to getting into college or landing a job — most auditions will require a Mozart concerto.
A little bit of knowledge can go a long way in getting the most of out of the experience. In Part I of this week-long series, a bit of history on the original manuscripts.
Studying the manuscripts
A good resource to consult is the book Das Horn bei Mozart by Hans Pizka. In a recent online check I could only find a copy for purchase at Amazon.com for the outrageous price of $595. It could not even be found on the author’s web site.
As an alternative, I would recommend a university music library. Das Horn Bei Mozart should be on the shelf as a reference or available through an inter-library loan. Either that or borrow a copy from a helpful horn professor who collects horn texts.
The beauty of this tome lies in its complete reproductions of Mozart’s original manuscripts. It wasn’t until consulting this book that I fully realized how fragmented and incomplete the Mozart concertos really are.
Another reliable resource for Mozart manuscripts would be the Neue Mozart-Ausgabe which again, might be found in a university music library. (Very soon this entire source will be digitized and made freely available online.)
Frankenstein’s monster
When studying the original manuscripts it becomes apparent that the only concerto that is more-or-less intact is K. 447, the 3rd concerto. The others — in one form or another — have been found in fragments or in incomplete sketches, and have been stitched and pieced together by music scholars and editors.
As a result, there are notational discrepancies between published editions. It probably does not help, as noted in Das Horn bei Mozart, that Henri Kling may have added a few of his own extra flourishes; most notably, this triplet passage preceding the recapitulation in the first movement of K. 495:
This passage appears in most current editions.
While Mozart left enough clues for scholars to fill in the gaps, putting the pieces back together again is a little bit like the classic fable of Humpty Dumpty. The hypothesis and debate on these concertos is an ongoing process.
For instance, John Ericson has pointed out that newer editions of the Concert Rondo K. 371 have 60 additional measures. A publication by the Harvard College Music Library confirms this and has cataloged it into a collection of K. 370b + K. 371.
This fascinating work, possibly commissioned for the Viennese hornist Jacob Eisen, is one of a number of incomplete concerti left by Mozart and one that suffered an unfortunate circumstance. In 1856, for the centennial of Mozart’s birth, the composer’s eldest son, Carl, decided to cut up and give away portions of the autograph (first movement) as souvenirs to several admirers of his father’s music.
The published version we know of as the Concert Rondo, according this Harvard source, was published by Henri Kling in 1909.
This movement entitled “Rondeau” by Mozart was, until recently, known in a misleading incomplete form and performed in a mutilated version for over half a century.
So it appears that while we have Kling to thank for at least making the Concert Rondo (and other Mozart horn concertos) more widely available, for all his good intentions he is also somewhat responsible for some of the current debate over what is what.
Other bits and pieces
I have also seen and heard several different versions in recent years of the Concerto in D K. 412 second movement rondo. An entirely new section within the Rondo adds a new perspective to the movement as a whole.
As for the concerto in D major, KV412 (1791), Mozart only left the opening Allegro and a score sketch of a rondo finale. The composer’s early death was no doubt the reason why he did not write a slow middle movement. The rondo was completed by Mozart’s pupil Franz Xaver Süßmayr on Good Friday, 6th April 1792, in a very free manner. He not only took no notice of the original accompaniment but also replaced the original middle section by a paraphrase of the Gregorian melody to the laments of Jeremiah, which are sung on Good Friday.We may assume that he only had Leutgeb’s copy of the horn part at his disposal. Nevertheless it was not until the 1970s that this familiar version (KV514), which has scarcely more than the rondo theme in common with the original, was shown not to be Mozart’s own work.
Based on other discovered fragments, it is also believed that Mozart may have written other several other horn concertos.
For myself, the E major K. 494a fragment is a real heart-breaker. What begins as something that promises to be a profound and major work, ends after only a few hundred measures.
My heart sinks whenever I hear or see this sad little fragment of something great that is never-to-be.
Other resources:
Next in this series – thoughts on editions.
On the left in the photo is the oldest Giardinelli horn mouthpiece I own. It is marked a 2C but in the terminology we are more used to it would be a C-2. The C signifies it has a Chambers cup (as in James Chambers, longtime Principal Horn of the New York Philharmonic) with a number 2 bore. [This number being the 
A Conn 5BN?!? I know that sounds a bit hard to believe and rather random in fact, but some of these are quite good. I have three of them actually, one being not nearly as good and two of them quite close with one having an edge over the other. It is on the right in the photo, with the original Conn gold plating. I am told that these were actually produced by outside jobbers, not by Conn itself. This is why these (and other classic brands) vary so much, it always really depends on who actually made the mouthpiece and where, especially these older mouthpieces that were not machine made on computer lathes. Even the most generic mouthpiece must have a few that slipped out that were actually quite good, totally up to specs and made by a very fine machinist. Just for the cheaper brands many more were shipped out that “looked like a mouthpiece” and that was good enough for the price point they sold at.