The string quartet is an ideal medium for a Classical era composer. The strings offer a wide range of expressive possibilities without the distractions of the more pungent sonorities of the wind instruments. The string quartet is also the ideal chamber ensemble, offering the intimacy of close conversation but at the same time, with its four voices, it can handle all the basic harmonies and dissonances of the style as well as four-part counterpoint.
We don't know too much about the occasions for the writing of much of Mozart's music for string quartet. The first group of quartets, probably written in Milan while there on tour with his father in 1772, are rather slight, inconsequential pieces in three movements often ending with a minuet. All the movements barely last more than ten minutes total. Here is K. 155 in D major:
Still, pretty good for a sixteen-year-old! What is missing here is the influence of Haydn, which was to prove enormous on Mozart's later chamber music. In the same year, 1772, while Mozart was in Italy, Haydn wrote the set of quartets, op. 20, that are considered by many to be the ones that really established the string quartet as the premiere chamber music ensemble over and above others such as the violin/piano sonata, the string or piano trio, the piano quintet and the various other combinations. Here is one of the two minor quartets from the six, the no. 5, in F minor:
What a contrast with the Mozart! This is more dramatic, more affetuoso and, instead of ending with a minuet, there is a fourth movement, a fugue with two subjects. When Mozart returned to Vienna in August and September of 1773, he wrote a new set of six quartets that were likely inspired in part by Haydn's. Here is K. 168 in F major from this new set. Not only is it in four movements, but the last one is a fugal finale!
Mozart is also using sonata form to structure the movements more, though the length is still only half of the Haydn example. But give him time, he probably just heard a Haydn quartet for the first time the week before! Mozart's father Leopold wrote to him in a letter once that he was sure that he, Wolfgang, could imitate any style or form, though of course the challenge of absorbing the influence of a composer as great as Haydn, is of a whole other level than that of copying someone like J. C. Bach.
For the next decade Mozart wrote no string quartets and did quite a bit of traveling in search of employment, including to Mannheim, where he heard the latest in orchestral virtuosity, and Paris. But in 1785 he published a new set of quartets and acknowledged the influence and inspiration of Haydn by dedicating the set to him. This was most unusual as dedications were usually made to noble patrons in exchange for their support. In 1781 Haydn had himself written a new and even more important set of string quartets, his op. 33, which Charles Rosen considers to be the real locus classicus of Classical Style--the set of pieces that truly defines and establishes all the elements of the "language". It was this set of quartets that Mozart was responding to with his "Haydn" Quartets. Here is Haydn's Quartet in E flat major, op. 33, no. 2.
Apart from the total confidence and aplomb we hear, Haydn is doing some very interesting things in the fourth movement. It is a rondo, which he begins to establish as the normal form for the last movement, but it is also one of the most comic Haydn ever wrote with a number of false endings that try to trick the audience into applauding prematurely. This gives the quartet its nickname "The Joke".
As I mentioned, Mozart responded to these quartets in 1785 with the set of "Haydn" quartets. Here is his dedication:
Perhaps the most famous of this very famous set is the last, nicknamed the "Dissonant" Quartet due to the extraordinary harmonic contortions of the introduction:
- To my dear friend Haydn,
- A father who had resolved to send his children out into the great world took it to be his duty to confide them to the protection and guidance of a very celebrated Man, especially when the latter by good fortune was at the same time his best Friend. Here they are then, O great Man and dearest Friend, these six children of mine. They are, it is true, the fruit of a long and laborious endeavor, yet the hope inspired in me by several Friends that it may be at least partly compensated encourages me, and I flatter myself that this offspring will serve to afford me solace one day. You, yourself, dearest friend, told me of your satisfaction with them during your last Visit to this Capital. It is this indulgence above all which urges me to commend them to you and encourages me to hope that they will not seem to you altogether unworthy of your favour. May it therefore please you to receive them kindly and to be their Father, Guide and Friend! From this moment I resign to you all my rights in them, begging you however to look indulgently upon the defects which the partiality of a Father's eye may have concealed from me, and in spite of them to continue in your generous Friendship for him who so greatly values it, in expectation of which I am, with all of my Heart, my dearest Friend, your most Sincere Friend,
- W.A. Mozart
Notice that this quartet is three times as long as Mozart's earlier excursions. He has fully taken up, and risen to, the challenge of Haydn.
This is one of the very, very few occasions in music history where the flow of influence is both clear and acknowledged. For his part Haydn paid back the compliment (of Mozart's dedication to him) by saying to Mozart's father when he first heard the quartets that "Before God, and as an honest man, I tell you that your son is the greatest composer known to me either in person or by name. He has taste, and, what is more, the most profound knowledge of composition."
Beethoven, for example, was far more reluctant to acknowledge Haydn's influence, commenting that while he had taken lessons from him, he had not learned anything. Ironically, he did, several times, write pieces that were significantly influenced by particular pieces of Mozart. In general, composers like to keep their influences hidden away so as to preserve the illusion of creation ab nihilo!