Elliott Carter in the context of "Charles Ives"

The term string quartet is a type of musical composition or a group of four people who play them. Many composers from the mid-18th century onwards wrote string quartets. The associated musical ensemble consists of two violinists, a violist, and a cellist.

The string quartet was developed into its present form by the Austrian composer Joseph Haydn, whose works in the 1750s established the ensemble as a group of four more-or-less equal partners. Since that time, the string quartet has been considered a prestigious form; writing for four instruments with broadly similar characteristics both constrains and tests a composer. String quartet composition flourished in the Classical era, and Mozart, Beethoven and Schubert each wrote a number of them. Many Romantic and early-twentieth-century composers composed string quartets, including Mendelssohn, Schumann, Brahms, Dvořák, Janáček, and Debussy. There was a slight lull in string quartet composition later in the 19th century, but it received a resurgence in the 20th century, with the Second Viennese School, Bartók, Shostakovich, Babbitt, and Carter producing highly regarded examples of the genre, and it remains an important and refined musical form.

Juliette Nadia Boulanger (French: [ʒyljɛt nadja bulɑ̃ʒe] ; 16 September 1887 – 22 October 1979) was a French music teacher, conductor and composer. She taught many of the leading composers and musicians of the 20th century, and also performed occasionally as a pianist and organist.

From a musical family, she achieved early honours as a student at the Conservatoire de Paris but, believing that she had no particular talent as a composer, she gave up writing music and became a teacher. In that capacity, she influenced generations of young composers, especially those from the United States and other English-speaking countries. Among her students were many important composers, soloists, arrangers, and conductors, including Grażyna Bacewicz, Daniel Barenboim, Lennox Berkeley, İdil Biret, Elliott Carter, Aaron Copland, David Diamond, John Eliot Gardiner, Philip Glass, Roy Harris, Quincy Jones, Gilbert Levine, Dinu Lipatti, Igor Markevitch, Julia Perry, Astor Piazzolla, Laurence Rosenthal, and over 250 others.

Leo Ornstein (born Lev Ornshteyn; Russian: Лев Орнштейн; c. December 11, 1895 – February 24, 2002) was an American experimental composer and pianist of the early twentieth century. His performances of works by avant-garde composers and his own innovative and even shocking pieces made him a cause célèbre on both sides of the Atlantic. The bulk of his experimental works were written for piano.

Ornstein was the first important composer to make extensive use of the tone cluster. As a pianist, he was considered a world-class talent. By the mid-1920s, he had walked away from his fame and soon disappeared from popular memory. Though he gave his last public concert before the age of forty, he continued writing music for another half-century and beyond. Largely forgotten for decades, he was rediscovered in the mid-1970s. Ornstein completed his eighth and final piano sonata in September 1990 at the age of ninety-four, making him the oldest published composer in history at the time (a mark since passed by Elliott Carter).