Ancestory of the piano

The first historical mention of instruments is in Genesis 4:21, where Jubal is called the father of all those who handle the harp and organ. The first instrument in history to have a "keyboard was the "Hydraulis', the precursor of the modern organ, built in Greece about 220 B.C. The Hydraulis was devised by Ctebius, an Alexandrian engineer, and practical theoretician as a demonstration of the principle of hydraulics. By the Second Century A.D. the organ was commonly used at important festivities in Greece and the Roman Empire.
The earliest keyboards were played with the hands, wrists, fists, knees, or feet. Spacing of the tabs, levers, pulls, etc., was according to the distance between the pipes they activated. This space could be 10 centimeters or more. Up to the 13th Century the scales were diatonic (as in GABCDEF) rather than the twelve tone chromatic scale we use today. A common arrangement was to use 'C' as the first key and include an extra note Bb", In a two-octave keyboard. Mechanisms added to 'abridge the gap" made it possible to space the keys evenly.
Throughout the 14th Century, the increasing practices of chromatism and transposition demanded the progressive addition of keys. Keyboard variations Included changes in the distance between the octaves, the size and shape of the keys (natural heads were stubby and short until the end of the 17th Century), depth of touch, color (such as dark naturals and light sharps), curved keyboards, rows of keys in different formats, more than twelve keys in a chromatic scale, etc. Keyboards reached five octaves by about 1700, six octaves by around 1800 and seven octaves by about 1900.
Modern pianos generally are of seven octaves and a third, while modern organ manuals usually have a maximum of five octaves. Some pianos have had up to eight octaves.
The idea of multiple strings on one instrument to play a scale with a hammer is not new. The dulcimer and it's relatives were played with hand held hammers. The earliest dulcimer of record is pictured In a 12th Century book cover (Kettlewell, 1980). W. J. Clark (1975) , h ow e v e r , credits the invention of the dulcimer (which he calls the first piano) to a Persian named Abu Nasre Farabi of the 9th Century A.D. who played a multi-stringed dulcimer called the Santur with two hand held mallets. The validity of this claim is disputed by Kettlewell.
The 14th and 15th Centuries saw the development of various kinds of keyboard stringed instruments. Those with hammers Included the chekker, dulce melos, and clavichord. Among the plucked instruments were the virginal, spinet and harpsichord.