The concerto is a genre we’ve already encountered, though it continues to evolve as we move into the Classical period. The concerto grosso falls out of fashion and is rarely composed after the Baroque. From this point forward in history, the term concerto refers to a solo concerto. Though the basic principle of contrasting a soloist with a full orchestra remains, changes are made to the form of the movements and the most commonly used solo instruments. While violin concertos remain popular, the advent of the piano and its rise in popularity makes it the dominant solo instrument in concerto compositions.
The Classical period brought the triumph of the solo concerto over the group or multiple concerto, assisted by the continued rise of the virtuoso soloist and the growing demand for up-to-date works for performance by amateurs. The former trend appears most obviously in the large number of violin concertos written by violinists for their own use.
The Classical period also witnessed the rise of the keyboard concerto. Until about 1770, the preferred stringed keyboard instrument was usually the harpsichord, but it was gradually supplanted by the piano. The most important composers of keyboard concertos before Wolfgang Amadeus Mozart were Bach’s sons. Vienna saw the production of many keyboard concertos. The last decades of the 18th century brought the rise of traveling piano virtuosos.
The concertos of this period show a broad transition from Baroque to Classical style, though many are more conservative than contemporaneous symphonies. Most are in three movements, though a significant minority adopt lighter two-movement patterns such as Allegro-Minuet and Allegro-Rondo. Dance and rondo finales are also frequent in three-movement concertos. Additionally, the ritornello form in the fast movements was replaced with the sonata form and rondo forms respectively.
Joseph Haydn’s concertos are mostly from his early career. Exceptions are the Piano Concerto in D, the Cello Concerto in D, and the Trumpet Concerto.
Of Mozart’s 23 original piano concertos, 17 date from his Viennese period. They are the crowning achievement of the concerto in the 18th century. Most of the works he wrote for Vienna are of a type that Mozart called grand concertos. These were intended for performance at his own subscription concerts, which were held in sizeable halls. They call for an orchestra that is much larger than a typical concerto of the time, especially in the expanded role assigned to the winds. The orchestra is rendered fully capable of sustaining a dramatic confrontation with the virtuosity and individuality of the soloist. Mozart’s approach in these concertos is often clearly symphonic, both in the application of formal symphonic principles, and in a Haydnesque interest in thematic unity in the later concertos. The range of styles and expression is greater than that of most other concertos of the period, from the comic-opera elements of K.467 to the Italianate lyricism of K.488, the tragic character of K.466 and 491 to the Beethovenian heroism of K.503.
Ludwig van Beethoven’s five piano concertos date from between c. 1793 and 1809, and he also wrote an early concertante work for piano and orchestra in 1784. They are longer than Mozart’s concertos, and call for even more virtuosity from the soloist. Beethoven’s Violin Concerto (1806) exhibits similar achievements – Mozart’s five violin concertos are all early works written in Salzburg in 1775.