Classical music

Since the Baroque era, the violin has been one of the most important of all instruments in classical music, for several reasons. The tone of the violin stands out above other instruments, making it appropriate for playing a melody line. In the hands of a good player, the violin is extremely agile, and can execute rapid and difficult sequences of notes.
Violins make up a large part of an orchestra, and are usually divided into two sections, known as the first and second violins. Composers often assign the melody to the first violins, while second violins play harmony, accompaniment patterns or the melody an octave lower than the first violins. A string quartet similarly has parts for first and second violins, as well as a viola part, and a bass instrument, such as the cello or, rarely, the double bass.

Continuous pitch instruments such as violin family instruments have the ability to play any pitch within their range, which, in the hands of great players, leads to wonderful range of harmonic colouring, making it possible for the instruments to be very expressive.[neutrality disputed] This ability is at its finest in the string quartet literature[neutrality disputed] where seamless changes from key to key and chord to chord create a kind of perfect harmonic world where even thirds ring with full resonance.[dubious – discuss]