Piano pedals have existed for almost as long as the modern piano itself, but they had a rocky start. While the modern piano accepted most of its final touches, the evolution of the piano pedal continued.
In 1722, the piano’s first tone-modifying mechanism came in the form of a hand stop, and was created by Father Piano himself: Bartolomeo Cristifori. The device positioned the hammers to strike only one piano string per key, which created a soft, relaxed timbre. But it was far from ideal; a spare hand was required to use it, meaning the pianist either repeatedly removed one hand from the keys, or practiced alongside a hand-stop operator. Thankfully, the mechanism was later modified to be operated by the knee, and became the predecessor to today’s una corda, or “soft,” pedal.
The next modification arrived soon after. Gottfried Silbermann — renowned European constructor of keyboard instruments — created a mechanism that lifted the dampers off of the strings, causing a reverb effect. This early sustain pedal had an advantage over most modern sustains: treble and bass notes could be controlled separately from one another; however, like the una corda, the sustain did not start off as a foot pedal; an impracticality which may have justified its early unpopularity. Today, the sustain is the most frequently used, and possibly the most favored, piano pedal.
Which brings us to the underdog: the sostenuto pedal. Created in the mid 1800s by Boisselot & Sons, it is by far the most misunderstood piano pedal. The sostenuto is constantly being replaced — or removed entirely — from its position as the middle pedal, and is only standard on an American grand. It allows certain notes to be “sustained” while other notes are left unaffected, and even piano leader Steinway saw potential in the pedal, opting to patent the idea three years after its début in 1844. But, surprisingly, the impressive effects of the sostenuto never caught on.
Alternative middle pedals have included practice rails, which muffle the notes for quiet practice; and the faux-sostenuto, which allows only the bass notes to resonate. Most modern pianos now have only two pedals, leaving the sostenuto –- one of the most unique and inspiring pedals –- to fade into antiquity.
via Piano Pedals – History of Piano Pedals.