These ancient metal trumpets were usually in one long straight section. it wasn't until around the 13th century that the tubing was folded back on itself one or more times to make the instrument compact. These natural instruments (as they had no valves) were limited in the notes they could play, as the length of tubing determined the key of the instrument. Different notes within the harmonic series were sounded by the
In the upper register of the instrument more notes are available and a scale of the home key can be played. Some players became so skilled in these difficult high notes that they could play melodies of great complexity on the natural trumpet, which led composers of the Baroque era such as Vivaldi and Bach to write highly decorated and florid solo parts for these trumpet virtuosos.
Haydn was a very prolific composer, as his known compositions number about 1,000 with probably many more unknown and lost works, but he wrote only 17 concertos. Haydn was a very competent pianist and violinist, but he didn't begin his career in music as a virtuoso performer. Mozart and Beethoven wrote concertos mostly for their own use before the public, especially Mozart who wrote 26 piano concertos alone. Haydn's reputation as a musician was based on his composition abilities as well as his handling of his musical duties while he was Kappelmeister to the Esterházy family, which is one reason for the low number of concertos he wrote. Haydn wrote the work in 1795 or 1796, and the concerto was performed by Weidinger in 1800. It is in 3 movements:
I. Allegro - The concerto begins with the presentation of motives by the orchestra. Haydn doesn't always have markedly different themes in his sonata movements, and this section is dominated by a martial theme that is punctuated by timpani and trumpets. When the solo trumpet enters it repeats the opening motive, and Haydn exploits the expanded compass of Weidinger's keyed trumpet with notes that would not be possible on a natural trumpet. The soloist expands upon the opening motives and enters into a dialogue with the orchestra in the development section, but the soloist remains in the spotlight. The recapitulation repeats the opening motive by the soloist until Haydn gives a fermata rest for the orchestra while the soloist plays a cadenza. The orchestra returns and brings the movement to a close.
II. Andante - Again Haydn exploits the keyed trumpet by giving it a gentle melody to play with the orchestra in this short movement.
III. Allegro - Haydn writes an energetic rondo as the final movement. The soloist plays rapid repeated notes, trills, and other dazzling figurations throughout the rondo. The entire compass of the trumpet from the bottom to the top is used to good effect throughout.
While Weidinger's trumpet allowed the player to hit notes not possible on the natural trumpet, his keyed system proved to be very difficult to learn and play. The keyed trumpet was eventually replaced by the valved trumpet in the 19th century, an instrument more versatile than the keyed version.