An orchestra is a large instrumental ensemble that contains sections of string, brass, woodwind, and percussion instruments. The term orchestra derives from the Greek ορχήστρα, the name for the area in front of an ancient Greek stage reserved for the Greek chorus. The orchestra grew by accretion throughout the 18th and 19th centuries, but changed very little in composition during the course of the 20th century.

A smaller-sized orchestra for this time period (of about fifty players or fewer) is called a chamber orchestra. A full-size orchestra (about 100 players) may sometimes be called a "symphony orchestra" or "philharmonic orchestra"; these modifiers do not necessarily indicate any strict difference in either the instrumental constitution or role of the orchestra, but can be useful to distinguish different ensembles based in the same city (for instance, the London Symphony Orchestra and the London Philharmonic Orchestra). A symphony orchestra will usually have over eighty musicians on its roster, in some cases over a hundred, but the actual number of musicians employed in a particular performance may vary according to the work being played and the size of the venue. A leading chamber orchestra might employ as many as fifty musicians; some are much smaller than that. Orchestras can also be found in schools. The term concert orchestra may sometimes be used (e.g., BBC Concert Orchestra; RTÉ Concert Orchestra)—no distinction is made on size of orchestra by use of this term, although their use is generally distinguished as for live concert. As such they are commonly chamber orchestras.

Bernard Johan Herman Haitink, CH, KBE (Dutch pronunciation: [ˈbɛrnɑrd ˈhaːi̯tɪŋk]) (born 4 March 1929) is a Dutch conductor and violinist.

Haitink was born in Amsterdam, the son of Willem Haitink and Anna Haitink. He studied music at the conservatoire in Amsterdam. He played the violin in orchestras before taking courses in conducting under Ferdinand Leitner in 1954 and 1955.

Haitink became second conductor of the Netherlands Radio Union Orchestra in 1955. He took the post of chief conductor of the Netherlands Radio Philharmonic in 1957. His conducting debut with the Concertgebouw Orchestra was on 7 November 1956, substituting for Carlo Maria Giulini. After the sudden death of Eduard van Beinum, Haitink was named first conductor of the Concertgebouw Orchestra on 1 September 1959. He became principal conductor of the Concertgebouw Orchestra in 1961, and shared that position jointly with Eugen Jochum until 1963, when Haitink became sole principal conductor. With the Concertgebouw Orchestra, Haitink made many recordings for the Philips label, and later Decca and EMI Classics, and toured widely with the orchestra.

Richard Georg Strauss (11 June 1864 – 8 September 1949) was a leading German composer of the late Romantic and early modern eras. He is known for his operas, which include Der Rosenkavalier and Salome; his Lieder, especially his Four Last Songs; and his tone poems and other orchestral works, such as Death and Transfiguration, Till Eulenspiegel's Merry Pranks, Also sprach Zarathustra, An Alpine Symphony, and Metamorphosen. Strauss was also a prominent conductor throughout Germany and Austria.

Strauss, along with Gustav Mahler, represents the late flowering of German Romanticism after Richard Wagner, in which pioneering subtleties of orchestration are combined with an advanced harmonic style.

Strauss was born on 11 June 1864, in Munich, the son of Franz Strauss, who was the principal horn player at the Court Opera in Munich. In his youth, he received a thorough musical education from his father. He wrote his first composition at the age of six, and continued to write music almost until his death.

The Chicago Symphony Orchestra (CSO) is an American orchestra based in Chicago, Illinois. It is one of the five American orchestras commonly referred to as the "Big Five". Founded in 1891, the Symphony makes its home at Orchestra Hall in Chicago and plays a summer season at the Ravinia Festival. The music director is Riccardo Muti, who began his tenure in 2010.

In 1891 Charles Norman Fay, a Chicago businessman, invited Theodore Thomas to establish an orchestra in Chicago. Conducted by Theodore Thomas under the name "Chicago Orchestra", the Orchestra played its first concert on October 16, 1891 at the Auditorium Theatre. It is one of the oldest orchestras in the United States, along with the New York Philharmonic, the Boston Symphony Orchestra and the Saint Louis Symphony Orchestra.

Orchestra Hall, now a component of the Symphony Center complex, was designed by Chicago architect Daniel H. Burnham and completed in 1904. Maestro Thomas served as music director for thirteen years until his death shortly after the orchestra's newly built residence was dedicated on December 14, 1904. The orchestra was renamed "Theodore Thomas Orchestra" in 1905 and today, Orchestra Hall still has "Theodore Thomas Orchestra Hall" inscribed in its façade.

The Toronto Symphony Orchestra (TSO) is a Canadian orchestra based in Toronto, Ontario.

The TSO was founded in 1922 as the New Symphony Orchestra, and gave its first concert at Massey Hall in April 1923. The orchestra changed its name to the Toronto Symphony Orchestra in 1927. The TSO continued to give regular concerts at Massey Hall from 1923 to 1982. Currently, TSO performances are held in Roy Thomson Hall.

Andrew Davis was the TSO's music director from 1975 to 1988, and is currently the orchestra's conductor laureate. The current TSO music director is Peter Oundjian, who was appointed to the post in January 2003 and formally became music director with the 2004-2005 season. In February 2007, Oundjian extended his contract with the TSO to 2012.

The orchestra had financial and audience size problems before the appointment of Oundjian as its music director. In 1992, TSO musicians had accepted a 16% pay cut because of a threat of bankruptcy to the orchestra, with a promise from management to make up the loss in subsequent contract negotiations. By 1999, this pay restoration had not happened, which led to an 11-week musicians' strike that autumn. Relations between the musicians and management had deteriorated to the point where music director Jukka-Pekka Saraste had offered to serve as mediator in the situation. In addition, there was a lack of public sympathy to the orchestra musicians' situation.