An assembly of musicians, an orchestra performs musical works written for a group. An orchestra usually includes stringed instruments played with a bow, such as violins, cellos, and violas; woodwind instruments, such as flutes, oboes, and bassoons; brass instruments (or horns), such as trumpets, trombones, and tubas; and percussion instruments, such as different kinds of drums, gongs, and the xylophone. An orchestra can be made up of any number of musicians and include whatever instruments are needed to perform a musical work, or composition.
In the Middle Ages different types of instruments were not played together. Instead, each kind of instrument had its own place and purpose. For example, woodwinds were played for outdoor occasions, while stringed instruments were heard in the royal court and chapels.
In about the 17th century composers began experimenting with mixing the different sounds each type of instrument produces. For example, an ensemble was required to play for the opera Orfeo, written in 1607 by the Italian composer Claudio Monteverdi. Later that century the French composer Jean-Baptiste Lully directed an orchestra for the royal court; it included mostly stringed instruments but also woodwinds and some brass.
The modern orchestra developed in the 1700s in Germany. There the basic makeup of the orchestra was established: four sections consisting of strings, woodwinds, brass, and percussion. During this period some instruments, such as the harpsichord and lute, were phased out. Newer instruments, such as the clarinet and the piano, were sometimes added.
Orchestras grew larger during the 1800s. Composers such as Hector Berlioz and Richard Wagner wrote music that called for many different kinds of instruments. It also required that many of each instrument be played. For example, the music for Berlioz's Requiem (1837) requires an enormous orchestra, including eight pairs of drums and four groups of brass instruments. Such 20th-century composers as Richard Strauss and Igor Stravinsky also created musical works demanding large ensembles.
In the early 1900s the chamber orchestra was developed. This is a scaled-down version of the orchestra, usually including one player for each part.
