Overview
Introduction
Despite its title, the Divertimento in B flat K254 is, in effect, Mozart’s first piano trio, written in Salzburg in 1776: ‘in effect’, because it is unlikely that Mozart had the opportunity to play it on a piano at that date. The principal keyboard instrument in the Mozart household at this period was a two-manual harpsichord. Mozart had, however, certainly played on fortepianos on his travels, and he was to do so again soon after writing this Divertimento. Letters to his father reveal that he played this work twice on the piano while he was in Munich in October 1777, on both occasions at the inn ‘Zum schwarzen Adler’ (The Black Eagle), where the proprietor was Franz Joseph Albert. He was described by Mozart as ‘a thoroughly sincere man and such a good friend’, and he was a music-lover who possessed a fortepiano. At one informal gathering of musicians, Mozart took the violin part of the Divertimento and played ‘as if I were the greatest fiddler in the whole of Europe’. The other occasion was a little private concert in honour of Albert’s birthday. This time Mozart played the piano part, giving the violin line to a visiting violinist who was a pupil of the great Tartini. Unfortunately he couldn’t sight-read, and kept on going wrong. Mozart writes: ‘There indeed I had a fine accompanist! In the Adagio I had to play his part for six bars.’ Back in Salzburg, Mozart’s father Leopold had better luck the following January, when two visiting musicians asked to hear Mozart’s sister play (presumably on the family harpsichord), and ‘accompanied Nannerl most excellently in your clavier trio in B flat’.
‘Accompany’, a word pianists have good reason to mistrust, is the right word in this case, though it is the stringed instruments that accompany the piano, not the other way round. Those letters reveal just the sort of informal setting for which this trio was designed. In this, unlike Mozart’s later trios, it follows the pattern of Haydn and a host of lesser composers in providing amateur keyboard-players with a delightful work for them to play on whatever instrument was available, with their friends accompanying them on violin and cello. Such works were published not as trios, but as ‘Sonatas for harpsichord or forte piano, with the accompaniment of violin and violoncello’. There was a very large market for them, particularly in Vienna and England.
In Mozart’s Divertimento, as in other accompanied sonatas, the cello shadows the bass of the piano almost throughout, almost in the manner of the Baroque continuo (Mozart’s layout of the parts in the score suggests something of this tradition, with the cello part below the piano, and the violin above). In the first movement the violin provides a charming foil to the piano’s right hand, sometimes filling in with an accompanying figure, at other times moving in thirds against the melody, or answering the piano’s phrases. As the work continues, the violin’s freedom increases, and it becomes a much more equal partner with the piano in the second and third movements. The first movement is a brisk Allegro assai, the finale a minuet-rondo, a form in which Mozart’s friend Johann Christian Bach excelled. The central Adagio looks forward to the later trios, with its melancholy touches of chromatic harmony, and the increasingly airborne decoration of its melody.
