Musical Form
Concerto
A soloist and an orchestra, in conversation and in contest.
Orchestral
A concerto sets a solo instrument - violin, piano, and cello are the most common, though almost any instrument has concertos written for it - against a full orchestra. The core idea is contrast and dialogue: the soloist and orchestra trade musical material, sometimes cooperating, sometimes seeming to compete, with the soloist typically given the more virtuosic, spotlighted material.
How a concerto is built
Most concertos from the Classical era onward have three movements, in a fast-slow-fast pattern: a substantial opening movement, a lyrical slow movement where the soloist can sing, and a lively finale, often a rondo with a catchy recurring tune.
The opening movement usually adapts sonata form to the two forces involved. The orchestra often presents the main themes first; then the soloist enters and presents them again in its own way, before the two develop the material together.
Near the end of a movement, the orchestra usually stops and leaves the soloist alone for the cadenza - an unaccompanied, often improvisatory passage designed to show off both technique and imagination. In Mozart's time soloists were expected to improvise their own cadenzas; from Beethoven onward, composers increasingly wrote them out, and in his "Emperor" Concerto Beethoven explicitly told the soloist not to add one.
How the concerto changed over time
The form took shape in the Baroque era in two flavors. The concerto grosso pits a small group of soloists against the full string band - Handel and Arcangelo Corelli wrote famous sets. The solo concerto, perfected by Vivaldi (who wrote more than 500 concertos), alternates a recurring orchestral refrain, the ritornello, with solo episodes. Bach's Brandenburg Concertos sit somewhere between the two.
The Classical era made the concerto a centerpiece of public concerts. Mozart wrote more than twenty piano concertos, mostly for himself to play, and many of them are among his finest music; his Clarinet Concerto (1791) and Haydn's Trumpet Concerto remain the cornerstones of those instruments' repertoire.
The Romantic era turned the soloist into a hero. Touring virtuosos made audiences gasp, and composers responded with concertos of tremendous difficulty and emotional sweep - Mendelssohn's Violin Concerto, Tchaikovsky's First Piano Concerto, Grieg's Piano Concerto, Brahms's two piano concertos and his violin concerto, and Rachmaninoff's Second and Third.
In the 20th century, the concerto kept evolving: Elgar's Cello Concerto (1919) is elegiac rather than showy, Prokofiev and Shostakovich gave it bite and irony, and Béla Bartók's Concerto for Orchestra (1943) turned the idea inside out by treating every section of the orchestra as a soloist.
Why it's tied to star performers
Because it's built around a single spotlighted performer, the concerto has always been closely tied to virtuosity and to specific star performers - many were written for, or by, the very soloists who would go on to premiere them. Mozart and Rachmaninoff premiered their own piano concertos; Mozart's Clarinet Concerto was written for his friend Anton Stadler. Even today, new concertos are usually commissioned with a particular soloist in mind.
Famous concertos
- Vivaldi - The Four Seasons (1725): four violin concertos, each a season.
- Mozart - Piano Concerto No. 21 (1785): its dreamy slow movement is one of his most famous melodies.
- Beethoven - Piano Concerto No. 5, "Emperor" and his Violin Concerto.
- Mendelssohn - Violin Concerto in E Minor (1844).
- Tchaikovsky - Piano Concerto No. 1 (1875): those thunderous opening chords.
- Rachmaninoff - Piano Concerto No. 2 (1901): lush, sweeping, and endlessly borrowed by film.
- Elgar - Cello Concerto (1919).
Where to start listening: Vivaldi's The Four Seasons is the friendliest entry point; Rachmaninoff's Piano Concerto No. 2 shows the Romantic concerto at its most lush and demanding. For something in between, the slow movement of Mozart's Piano Concerto No. 21 is hard to resist.