Piano Trio in B flat major, K.502

Mozart was by no means the first major composer two write a piano trio. But he was the first to treat the three instruments more or less as equals, releasing the cello from the subservient bass-line position to which Haydn customarily consigned it. It was a slow process, however. In the three earliest of the six piano trios Mozazrt wrote in Vienna in the 1780s the piano and violin are still reluctant to concede anything of their inherited privileges. In the first movement of K.502 the cello does, on the other hand, get a share of the melodic line in company with the violin and at one particularly interesting point, where a new theme is introduced at the beginning of the development section, it is linked in parallel to the melodic line two octaves and a third above on the piano. Melodic interest in the Larghetto, a slow rondo, is reserved exclusively for the piano and violin – the lovely main theme itself and the scarcely less expressive material of the two episodes. The final Allegretto, another rondo, seems at first to be similarly inclined in favour of the piano and violin. The cello does, however, get involved in the contrapuntal development of the main theme in the middle of the movement and, in an inspired coda, it is released from the bass line to provoke its companions into securing a brilliant ending.

When, on returning to the medium in 1786, Mozart liberated the cello from its conventional role of doubling the bass line of the piano he created the modern piano trio. Democracy was still slow to develop, however - and not only in the piano trios of Haydn, who continued to tie the cello down well into the 1790s. Even in Mozart’s Piano Trios in G and B flat major, the earliest of the five he wrote in Vienna in the 1780s, the piano and the violin are reluctant to concede anything of their customary prominence to the cello.

In the opening bars of the first movement of K.502, while the piano introduces the main theme and the violin adds a brief but scarcely less significant phrase of its own, the cello simply mirrors the bass line of the piano. When they come to the second subject it is the piano that cheerfully announces that the new theme is to be nothing more than the old one transposed to the dominant. At this point, however, the cello does get to repeat the theme in tenths with the violin before the two instruments engage in an exchange of comments on its opening phrase. The next surprise, a new theme interpolated by the violin in F major at the beginning of the development, leads to a similar situation, the cello line now linked in parallel to the melodic line two octaves and a third above in the pianist’s right hand. If that is a case of holding the cello at arm’s length, the recapitulation of the second subject with violin and cello in intimate thirds is some compensation.

Melodic interest in the Larghetto, a slow rondo in E flat major, is reserved exclusively for the piano and violin - the lovely main theme itself and the scarcely less expressive material of the two episodes in B flat and A flat major respectively. Even so, in the most beautifully scored passage in the whole movement, where the main theme is recalled by the piano for the last time against discreetly sustained contrapuntal lines on the strings, the three colours are for the first time combined in one of the essential piano-trio textures.

The final Allegretto, another rondo, seems at first to be similarly biased in favour of the piano and violin. The cello has nothing much to do with the introduction of the main theme - a lively variant of that of the preceding movement - and in the first episode little more is required of it than to provide a humble accompaniment to the tune on the violin. It does, however, get involved with the contrapuntal development of the main theme in the middle of the movement and, in an inspired coda based on the violin tune from the first episode, it is released from the bass line to provoke its companions into securing a brilliant ending.

When Mozart liberated the cello from its conventional role of doubling the bass line of the piano, even if he stopped short of awarding it full equality with the violin, he created the modern piano trio. In his first mature piece for the three instruments, the Divertimento in B flat, K.254, written in Salzburg in 1776, he had observed the trio conventions of the time. Ten years later in Vienna, however, he demonstrated that it was no longer technically necessary, let alone aesthetically desirable, to preserve the textural hierarchy as it was. Although Haydn continued well into the 1790s to tie the cello down to the bass line, after the publication of Mozart’s Piano Trios in G and B flat major in 1786 democracy was to become as essential to the piano trio as it already was to the string quartet.

One of the first projects Beethoven undertook after his arrival in Vienna was to develop the Mozart model in his three Piano Trios, Op.1. He did it most successfully and most radically in No.3 in C minor - the one which, not surprisingly perhaps, Haydn advised him not to publish. Of course, he did publish it, along with the other two in 1795, and so began the process of realigning the basic relationship between the three instruments. The two later Piano Trios, Op.70, and the “Archduke,” Op.97, not only confirmed the effectiveness of the new arrangement - with the cello now linked to the violin to form one side of a broadly two-part texture, with strings on the one hand balanced by the piano on the other - but established it as standard for a hundred and fifty years or so.

Wolfgang Amadeus Mozart (1756-1791)

Piano Trio in B flat major, K.502

Allegro

Larghetto

Allegretto

In the Piano Trios in G and B flat major, the earliest of five such scores written in Vienna in the 1780s, the piano and the violin are slow to concede anything of their customary prominence to the cello. In the opening bars of the first movement of K.502, while the piano introduces the main theme and the violin adds a brief but scarcely less significant phrase of its own, the cello simply mirrors the bass line of the piano. When they come to the second subject it is the piano that cheerfully announces that the new theme is to be nothing more than the old one transposed to the dominant. At this point, however, the cello does get to repeat the theme in tenths with the violin before the two instruments engage in an exchange of comments on its opening phrase. The next surprise, a really new theme interpolated by the violin in F major at the beginning of the development, leads to a similar situation, the cello line now linked in parallel to the melodic line two octaves and a third above in the pianist’s right hand. If that is a case of holding the cello at arm’s length, the recapitulation of the second subject with violin and cello in intimate thirds is some compensation.

Melodic interest in the Larghetto, a slow rondo in E flat major, is reserved exclusively for the piano and violin - the lovely main theme itself and the scarcely less expressive material of the two episodes in B flat and A flat major respectively. Even so, in the most beautifully scored passage in the whole movement, where the main theme is recalled by the piano for the last time against discreetly sustained contrapuntal lines on the strings, the three colours are for the first time combined in one of the essential piano-trio textures.

The final Allegretto, another rondo, seems at first to be similarly biased in favour of the piano and violin. The cello has nothing much to do with the introduction of the main theme - a lively variant of that of the preceding movement - and in the first episode little more is required of it than to provide a humble accompaniment to the tune on the violin. It does, however, get involved with the contrapuntal development of the main theme in the middle of the movement and, in an inspired coda based on the violin tune from the first episode, it is released from the bass line to provoke its companions into securing a brilliant ending.