A sustain pedal or sustaining pedal (also damper pedal or loud pedal) is the most commonly used pedal in a modern piano[citation needed]. It is typically the rightmost of two or three pedals. When pressed, the sustain pedal "sustains" all the strings on the piano, removing the dampers from all strings and allowing them to vibrate freely. This serves two purposes. First, it assists the pianist in producing a legato (playing smoothly connected notes) in passages where no fingering is available to make this otherwise possible. Secondly, raising the damper pedal causes all the strings to vibrate sympathetically with whichever notes are being played, which greatly enriches the piano's tone.
History
A device similar to the damper pedal in effect was invented by the piano pioneer Gottfried Silbermann; it was operated by the player's hands rather than a pedal. A later eminent early builder, Johann Andreas Stein, may have been the first to allow the player to lift the dampers while still playing; his device was controlled by a knee lever.
Until the onset of the Romantic era in music, the damper pedal was considered a special effect, used only in particular circumstances (see Piano history and musical performance). Only with the Romantics did a fairly constant use of the pedal come to be regarded as an essential element of piano sound.
Specifying pedaling in musical compositions
Appropriate use of the pedal is often left to the musician's discretion, but composers and music editors also use pedal marks to notate it. The most common symbol for this is a horizontal line below the grand staff, which lifts up and down with the pedal. An alternative (and older) notation is the use of
indicating where the sustain pedal should be depressed, and an asterisk 
showing where it should be lifted. Occasionally there is a general direction at the start of a movement instructing that the sustain pedal be applied continuously throughout. This may be marked with senza sordini ("without dampers"), or similar wording (see Moonlight Sonata for a famous example).
History
A device similar to the damper pedal in effect was invented by the piano pioneer Gottfried Silbermann; it was operated by the player's hands rather than a pedal. A later eminent early builder, Johann Andreas Stein, may have been the first to allow the player to lift the dampers while still playing; his device was controlled by a knee lever.
Until the onset of the Romantic era in music, the damper pedal was considered a special effect, used only in particular circumstances (see Piano history and musical performance). Only with the Romantics did a fairly constant use of the pedal come to be regarded as an essential element of piano sound.
Specifying pedaling in musical compositions
Appropriate use of the pedal is often left to the musician's discretion, but composers and music editors also use pedal marks to notate it. The most common symbol for this is a horizontal line below the grand staff, which lifts up and down with the pedal. An alternative (and older) notation is the use of
indicating where the sustain pedal should be depressed, and an asterisk showing where it should be lifted. Occasionally there is a general direction at the start of a movement instructing that the sustain pedal be applied continuously throughout. This may be marked with senza sordini ("without dampers"), or similar wording (see Moonlight Sonata for a famous example).
