The members of the Haffner family were good friends of the Mozarts in Salzburg. Sigmund Haffner the Elder (1699-1772) had been a wealthy merchant and the mayor of the city in whose house a great deal of music was made, with both Leopold and Wolfgang Mozart frequently participating. The relations continued after the mayor’s death, and when his daughter Maria Elisabeth Haffner (1753-1784) was going to be married in 1776, Mozart was asked to write some festive music for the wedding. The “Haffner” Serenade (K. 250) was so successful that six years later, when another cause for celebration arose, the composer received another commission from the family. This time the occasion was Sigmund Haffner the Younger’s (1756-1787) elevation to nobility.

In the meantime, Mozart had left his native city and moved to Vienna, where his fame was rapidly advancing. When the request from Salzburg reached him in July 1782, his opera The Abduction from the Seraglio had just been premiered. He was busy arranging selections from it for wind ensemble (in those pre-copyright days, someone else could beat him to it and secure the not inconsiderable profits!). In addition, his wedding with Constanze Weber was imminent (August 4) and he was preparing to move to new quarters.  In these circumstances, the composition of the new symphony went slower than father Leopold – anxious for the symphony to arrive in time for the festivities – might have wished.

Nevertheless, Mozart seems to have managed to send the score to Salzburg before the end of August, since on the 24th of that month he was able to write to his father: “I am delighted that the symphony is to your taste.”

We can tell from the music that the symphony had originally been intended as a second “Haffner” Serenade. Its tone is bright and exuberant, without any dramatic outbursts or the slightest trace of sadness and gloom. The opening theme – with its wide octave leaps in unison – is quite an exceptional melody, and it is handled in a most original fashion. It is, in fact, the only significant melodic material in the movement, and is reintroduced when we would expect a second theme, with the only difference that it is now played softly and treated contrapuntally.

There is hardly a moment in the symphony when we don’t hear at least the rhythm of the theme. The development section invests the melody with yet another character, exploring briefly the minor mode and adding a sensual sigh-motif as a counterpoint played by the oboe and the bassoon. The recapitulation runs exactly parallel to the exposition, except for the very end, where the last motif is changed from a jaunty staccato (short, separated notes) to a delicate chromatic scale as a mock-tearful farewell gesture.

The second movement, marked Andante, is less slow than most second movements.  Its tone, not surprisingly after what we know about the symphony’s genesis, is that of an easy-going, peaceful serenade. The exquisite melodies flow one after another, and each has a distinctive touch that no other composer could ever have invented.

 The brief and concise third-movement Minuet is based on a fanfare motif in which the trumpets and timpani play an important part. The movement’s Trio section, whose melody is harmonized in the so-called “horn” style (using thirds, fifths, and sixths), seems to have been inspired by popular Ländler tunes.

Mozart wrote that the fourth-movement Presto finale should go “as fast as possible.”  It is an extremely lively piece based on a simple tune, developed and varied in a most ingenious way. It starts softly on the strings, but the entire orchestra with trumpets and kettledrums soon joins in. The second theme, by contrast, is scored for strings and woodwinds only. There is a brief coda, or a sort of musical postscript, which repeats the soft-loud scheme of the main melody a final time, before the jubilant ending played by the full orchestra.

The “Haffner” Symphony soon became known beyond Salzburg.  It was an instant success in Vienna. As Mozart wrote to his father after the Viennese premiere (which, according to the custom of the day, opened with the first three movements of the symphony and closed with the Finale, with piano music, improvisation, and vocal selections in between):
The theatre could not have been more crowded and….every box was full.  But what pleased me most of all was that His Majesty the Emperor [Joseph II] was present and, goodness! – how delighted he was and how he applauded me!  It is his custom to send money to the box office before going to the theatre; otherwise I should have been fully justified in counting on a larger sum, for really his delight was beyond all bounds.  He sent 25 ducats.

The “Haffner” Symphony was performed in Mozart’s lifetime in several cities outside Vienna, including Paris, where it was heard in the famous concert series “Concerts spirituels.” After a 1786 concert in Germany, an anonymous correspondent wrote in the Magazin der Musik:
The concert began with a new Symphony in D by Mozart, which was all the more welcome to me because I had already long been desirous of hearing it. Chamber-musician Lehritter….led the orchestra – which consisted of approximately 45 or 46 mostly young artists – with so much fire and solidity that I stood there full of astonishment… I consider Mozart’s symphony itself a masterpiece of harmony.