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.

The Mahler Chamber Orchestra [1] is a professional touring chamber orchestra founded by Claudio Abbado and former members of the Gustav Mahler Youth Orchestra in 1997.

The MCO appears throughout the year in about 60-70 concerts and performances. It consists of 60 musicians from 17 different nations. Its activities include concerts, opera projects, chamber music as well as CD recordings. Strong artistic links have been established with Daniel Harding (principal guest conductor 1998-2003, music director since September 2003) and Claudio Abbado. The MCO has stable residencies in Ferrara (Ferrara Musica, honorary president: Claudio Abbado), Aix-en-Provence (Festival international d'art lyrique d'Aix-en-Provence), Toblach (Gustav Mahler Musikwochen), Lucerne (Lucerne Festival), Salzburg (Mozartwochen) and Landshut.

The MCO's repertoire reaches from baroque to contemporary music. The MCO is a free financed orchestra without any state support. Friends and sponsors are needed to maintain the artistic life of the orchestra.

Edward Benjamin Britten, Baron Britten,OM CH (22 November 1913 – 4 December 1976) was an English composer, conductor, and pianist; and one of the central figures of 20th century British classical music. He showed talent from an early age, and first came to public attention with the a cappella choral work A Boy Was Born in 1934. With the premiere of his opera Peter Grimes in 1945, he leapt to international fame. For the next fifteen years he devoted much of his compositional attention to writing operas, establishing him as one of the leading 20th century figures in this genre.

Britten's interests as a composer were wide-ranging; he produced important music in such varied genres as orchestral, choral, solo vocal (much of it written for his life partner, tenor Peter Pears), chamber and instrumental, as well as film music. He also took a great interest in writing music for children and amateur performers, and was an outstanding pianist and conductor.

Britten was born in Lowestoft, Suffolk, on 22 November 1913, the youngest of four children. His father, Robert, was a dentist, and his mother Edith, a talented amateur musician who gave Britten his first lessons in piano and notation. He showed musical gifts very early in life, making his first attempts at composition aged five, and thereafter composing prolifically as a child. He started piano lessons with a teacher from his pre-prep school when aged 7, and viola lessons with Audrey Alston when 10 years old.