A specific category of concerto arose for the first time in the late 17th century. Arcangelo Corelli, a leading violinist and composer of the then-prominent, north Italian violin school, used the new title concerto grosso for the 12 instrumental pieces of his opus 6 (probably written c. 1680-85 and published posthumously c. 1714). These works employed a string orchestra—called the concerto grosso, the ripieno ("full" In music, a repeating section: in the 14th and 15th centuries, it was the refrain at the end of each madrigal verse, the music being treated separately from the previous material, often including a change of metre; in 17th-century opera and song, it was an instrumental conclusion or refrain added to the end of an aria or song.), or the tutti ("all")—in contrast to and together with a smaller solo group, called the concertino, which in Corelli's pieces consisted of only three players. His concertos, comprising a series of short movements of contrasting meter and tempo, were virtually identical in style and form to the dominant chamber-music genre of the time, the trio sonata. The new concerto grosso was taken up by other composers such as Giuseppe Torelli, an Italian, and it soon developed its own style, characterized by decisive opening themes based on broken chords; driving, repetitive rhythms; and harmonic patterns working to define a home key, or tonic. It continued in popularity throughout the baroque era, important late examples being the six Brandenburg Concertos of Bach. The essential characteristic remained the use of a string orchestra set in varying degrees of opposition to a number of solo instruments—winds, strings, or a combination.
The concerto grosso spawned a subcategory: Solo concertos were written at first for violin, trumpet, or oboe by such Italian composers as Torelli and Tomaso Albinoni. Soon they were composed for a wide variety of solo instruments; among the most notable were the many solo concertos of the Italian composer Antonio Vivaldi. A growing number of instrumental virtuosos, especially violinists, exploited the solo concerto as a vehicle for their performances, both in churches and in the increasing number of private and semipublic concerts.
These early works established the large plan that remained standard for the solo concerto until about 1900: a succession of three movements in the order fast-slow-fast, with the middle movement in a different key from the main key of the first and last movements. In fast movements the solo passages were expanded into long sections, often dominated by rapid figuration; these sections were alternated among four or five recurring sections for full orchestra, called ritornellos (the combined sections being called ritornello form). Before the closing ritornello in at least one of the movements, the soloist was expected to display technical and musical skill in an improvised passage called a cadenza. The cadenza remained a standard element of the concerto through the classical and romantic eras, although later composers usually wrote it out instead of relying on the performer's taste and abilities.
The decisive musical change in the mid-18th century from the baroque to the classical style could not fail to affect the concerto. Aside from a brief flowering of a French offshoot called the symphonie concertante, the concerto grosso died out in favor of the symphony, which had absorbed many of its features. The solo concerto, however, persisted as an indispensable virtuoso vehicle, especially for the composer-performer. The newly prominent piano gradually supplanted the violin as the preferred concerto solo instrument. It was the favorite instrument of both Wolfgang Amadeus Mozart, who wrote the most important concertos (most of them for piano) of the late 18th century, and Ludwig van Beethoven, whose five piano concertos and one violin concerto (1801-11) brought the form to a peak of development.
During the classical era the concerto grew longer. Its form reflected a compromise among the traditional ritornello form, the requirement for virtuosic display, and the new style and forms being developed in the symphony. First movements were constructed in a variant of ritornello form in which both the first ritornello and the first solo section resembled the exposition section of the first movement of a symphony; the rest of the movement also proceeded like a symphony's first movement, but with solo and orchestra playing together or alternating. The final movement was usually a rondo in which the solo played a recurring refrain. Slow movements remained less strictly prescribed in form. Like symphonies, concertos became large, they were individually distinctive works intended for performance in a public concert hall before a large audience.