2. Ancestry & Invention
The earliest recorded keyboard instrument is the hydraulis, invented in the third century BC by the Greek scientist Ctesibius. The hydraulis, which used only the seven notes of the major scale, used water pressure from an elevated reservoir to create the wind necessary to power a set of organ pipes. During the seventh century AD the hydraulis was adopted by the Catholic Church, in whose hands it slowly developed into the modern church organ: it would be more than five hundred years before the seven notes of the hydraulis were augmented by five chromatic notes (the black keys of contemporary keyboard instruments).
While the piano inherited its keyboard layout from the organ, it can also trace its lineage to the hammered dulcimer, whose sound-producing mechanism also involves striking taut strings with a hammer. In the case of the dulcimer, these hammers are hand-held, while the pianos hammers are connected via a complex mechanism to the keyboard.
Invented in the 1700s by Bartolomeo Cristofori di Francesco, the pianoforte represented a major advance over its immediate predecessors the harpsichord and the clavichord, in that it allowed for a higher degree of dynamic variation - hence its original full name, clavicembalo con piano e forte (harpsichord with loud and soft). This greater dynamic range is directly inherited from the dulcimer.
The harpsichord produces sound by plucking the strings with a plectrum; the strings of the clavichord are struck by a small metal blade called a tangent, which remains in contact with the string, acting both as hammer and fret, determining the effective length of the string and hence the pitch of the note. The pianos strings are struck with a hammer which immediately falls away from the string, leaving it free to vibrate. This produces greater sustain than the clavichord, where the continued contact between the string and the tangent tends to dampen the sound, and greater dynamic range than the harpsichord.