The Haydn Duos K423 and K424: Legend or Fact??
In 1808 we find the following report in the "Biography Sketch of Michael Haydn...Written for the Benefit of his Widow:
"Michael Haydn was supposed, on high orders, to write duets for Violin and Viola. However, he could not supply them by the appointed time because he had become seriously ill, and was incapacitated for longer than was anticipated. The patron was not prepared to offer a quid pro quo: perhaps he was too little, or even falsely informed of Haydn's circumstances. Mozart, who visited him daily, heard of this, sat down and wrote for his afflicted friend with such indefatigable industry that the Duets were finished in a few days, and were given out under Michael Haydn's name. In later times we have often delighted ourselves with these marvelous works of charity, the original of which our master preserved as a sacred relic".
This biographical sketch is usually attributed to Georg Schinn and Jospeh Otter, both students of Michael Haydn. However it may also have been based, at least in part on material provided by Haydn's friend P. Werigand Rettensteiner.
Over the years this anecdote has been quoted, altered and embellished. The anecdote was used in the Nissen biography, in a slightly abridged and altered form. He added these lines after the anecdote: "These Duets were after some years known as Mozart's work and were printed by André in Offenbach; but he himself had not published them".
The autograph of the first Duo by Mozart contains a signed verification by Aloys Fuchs, dated 1850, that "these are the scores of he 2 Duets which Mozart on request of Michael Haydn wrote--as owing to illness an accepted obligation of the delivery of 6 Duets he could not fulfill--entirely written by Mozart's own hand, and that this full score as the 1st draft of this composition is to be regarded".
By the time of Otto Jahn the anecdote had changed to Haydn being ordered by the Archbishop to compose some Duets for Violin and Viola, perhaps for his special use. The Archbishop threatened to deprive him of his salary. So Mozart, hearing of this difficulty, visited Haydn daily, wrote by his bedside and completed the Duets, handing them over to the Archbishop in Haydn's name. By the time of Abert/Jahn Mozart was not only helping his friend but taking amusement in writing the Duets unknown to his "old tormentor", and using the humor of the "roguish theme" in the last movement of the Bb Duo as a private joke toward the Archbishop. Thus the story is told and retold, up to today, as in 1987 it was written "most likely [the Archbishop] never learned that he had before him two compositions of this former Concertmaster and Church Organist, W.A. Mozart...".
But does the story have merit?
Let us break it down, to find out. First, as to dating. Mozart was in Salzburg to visit his family in late summer to October 1783, thus this had to take place at this time. There is no record of Michael Haydn be seriously ill during this time, but of course we might not know if he was, or for how long.
We do have two Duets for Violin and Viola by Mozart--K423 and K424. And there are 4 Duets for Violin and Viola by Michael Haydn. Michael Haydn's Duets are in C, D, Eb and F; Mozart's are in G and Bb, so none are in the same key. Mozart's autographs are not signed or dated by him. The only indications on the autograph in his hand are the tempo markings. It appears Mozart could have intended these autographs to be inserted into other works to form a complete cycle; and of course to conceal his authorship.
But there are some problems with this. First and foremost, Mozart's style is out of place with Michael Haydn's style. For example Haydn's duets lacked the contrapuntal ingredient that Mozart's have. Surely the Archbishop--or his copyists--would have recognized Mozart's musical style, not to mention his musical handwriting. Even if the Archbishop himself did not see the autographs, one can not imagine his copyists not telling him of the autograph handwriting discrepancies. Surely their allegiance was to the Archbishop--not Haydn or Mozart.
There is no reason to doubt Mozart wrote these Duos and that they were composed in Salzburg. The paper they are written on is used in other autographs from around this time. On December 6, 1783, Mozart wrote to his father in Salzburg "I would ask you please to send me as soon as possible my Idomeneo--the two Violin Duetten, and Seb. Bach's fugues". Again on December 24, 1783, he writes "I ask you again to send to me the 2 Duetten, Bach's fugues and especially Idomeneo". As Mozart did not mention them again, one would assume he received them. No doubt he received copies, as Constanze never mentioned the autographs in her dealing with publishers later, and Andre in his 1833 catalogue listed them under the classification "Mozart's Compositions after authentic copies in parts". And supposedly Michael Haydn had the autographs. However there is no evidence--other than the anecdote--that he had the autographs.
But were these Duets written for Michael Haydn as the anecdote says? Mozart does not refer to them as the Duetten he wrote for Haydn, or anything similar to this in his letters of December 1783. Nannerl does not refer to this incident in her diary, but as Agnes Selby has pointed out this would not be unusual, and means nothing. Nothing is ever said of this incident in any later reminisce by Nannerl. No mention of the incident is ever mentioned between father, son, sister in later letters either. Constanze does not mention it, either--Nissen does, but obviously only through the Michael Haydn Biography Sketch.
Alfred Einstein had this problem with the story. "It is difficult to see why six duos would have to be finished by a certain day". Furthermore, if these Duets were not for publishing, why were six required; would not four be sufficient? Even for publishing, sets of 3 were published regularly of chamber music.
The 2 Mozart Duets (K423, K424) were first published by Artaria in 1792, with no mention of a Michael Haydn connection. Before the anecdote of 1808 they were published 7 more times, all without a Michael Haydn connection. These 2 Duos were never published nor have they been found in manuscript attributed to Michael Haydn.
However there are connections.
On June 18, 1788 the Vienna businessman Johann Traeg put the following notice in the 'Wiener Zeitung': "Six Duets for Violin and Viola. The first 4 are by M. Haydnreich the 5th and 6th by Mozart". The same notice was placed on July 2, 1788, with the name correctly spelled "M. Haydn". No copies of this have ever been found. However there is a manuscript copy of Haydn's Duos in Zabreb, Yugoslavia that states the dedicatee of the Duos was Archbishop Colloredo. Although only 2 of Haydn's 4 Duos are still preserved in this manuscript, the wording of the title page refers to an older source which may have contained all six. Dietrich Berke believes this may be a copy of the Traeg printing.
There was a review in the 'Augsburger musikalischer Merkur auf das Jahr 1795' of an edition of SIX Sonatas for Violin and Viola by Michael Haydn to be available by the Gombart music shop in Augsburg. The review states "the third Sonata is entirely filled with Mozart's spirit". It talks of beautiful melodies, rich harmony, exquisite ideas, etc. The reviewer states "the work begins with an Allegro, continues with a touching Adagio, and ends with the daintiest Rondo imaginable". This description fits the movements and tempos of Mozart's K423. However it also fits exactly to Haydn Sonata in C. Unfortunately there is no copy of this printing known, if it ever appeared.
The Michael Haydn Duos were published ca. 1801 by Artaria in Vienna in two volumes of 2 Duos each. They were again published by Mollo in Vienna around 1805 and Sieber in Paris in 1813--however by Sieber under Joseph Haydn's name. None of these stated any connection to Mozart.
So, did Mozart composed these Duos to be added to Michael Haydn's already completed four?
Einstein believed: "Probably he [Mozart] had been simply struck by a desire to try his hand at this form, too". I think this is logical. I have 3 of the 4 Michael Haydn Duos in my collection, and there is a marked difference in style between the two sets of compositions. I don't think Mozart attempted to imitate Michael Haydn's style. The first Duo by Haydn (in C) comes closest to Mozart style, but lacks the spark of Mozart (but of course this is only opinion, and certainly influenced I guess by me knowing who composed which Sonatas--however Mozart's counterpoint is lacking for sure in the Haydn works).
I will let you digest the above facts and decide for yourself: Fact or Legend.