It was primarily in the last thirty years of the eighteenth century that the symphonie concertante had won popularity, particularly in Paris. It was as a result of his visit to the city in 1778 that Mozart wrote his own four completed examples of the genre and started work on two more, one with a solo string trio and the other for solo violin and piano. In German-speaking territory the form won less immediate favour, although concertos for two or more solo instruments continued to have a place. Beethoven's single contribution was the so-called Triple Concerto of 1804, the Concerto in C major for violin, cello and piano, Opus 56. This was apparently written for the Archduke Rudolph, son of the late Emperor Leopold II, who became Beethoven's pupil at the age of fifteen, in 1803. The Archduke continued his study with Beethoven intermittently over the next twenty years, making his own contribution to cultural life in his compositions and, above all, in his patronage and the very practical and tactful help he extended to his teacher, for whom he was instrumental in providing, from 1809, a pension. The Triple Concerto makes relatively modest demands on the pianist, the Archduke himself, but presents greater technical challenges to the string players, the violinist Carl August Seidler and the veteran cellist Anton Kraft, who had served Haydn at Esterháza from 1778 until 1790 and from 1795 was in the service of Prince Lobkowitz in Vienna. It was for these performers that the work was originally intended. The work was offered, before its completion, to various publishers and finally appeared in 1807, issued by the Vienna Bureau des Arts et d'Industrie (Kunst- und Industrie-Comptoir), in which Joseph von Sonnleithner, a close friend of Schubert, had an interest. The published concerto was dedicated to Prince Lobkowitz and the first known public performance was given in a concert organized by the violinist Schuppanzigh at the Augartensaal in May 1808. On this occasion it apparently made little impression on those who heard it, a failing that Beethoven's assiduous friend Schindler attributed to the lack of seriousness of the performers.

The Triple Concerto starts with an ascending figure played by cellos and double basses, an important rhythmic motif in what follows, in both the principal and secondary subject material. The orchestral exposition leads to a hushed repetition, from the first violins, of the key note of C, above which the solo cello enters, establishing its primacy in the solo ensemble. It is joined by the solo violin, the two instruments preparing for the entry of the piano. The exposition is of some length, allowing each of the solo instruments a measure of prominence in figuration that often recalls, in the writing for violin and cello, the use Mozart made of violin and viola in his Sinfonia Concertante for those instruments. The A flat major slow movement, introduced by muted strings, allow, the solo cello the statement of the singing principal theme. The piano provides a gentle accompaniment, as violin and cello join in the melodic material, moving towards a modulation that allows the direct introduction of the final Rondo alla Polacca, where the solo cello again introduces the principal theme, used to frame episodes of contrasting melody and key. There is a change from triple to a rapid duple time for the closing Allegro, which provides the equivalent of a cadenza, before the coda proper.