It is not known exactly when Cristofori first built a piano. An inventory fabricated by his employers, the Medici family, indicates the existence of a piano by the year 1700; another http://www.pianocovers.com/Grand-Piano-Covers-s/3.htm document of doubtful authenticity indicates a date of 1698. The three Cristofori pianos that survive today date from the 1720s.

Some Bösendorfer pianos extend the normal circle downwards to F0, with one other model going as far as a last C0, bureaucratic a full eight octave range. These extra keys are sometimes concealed under a small hinged lid that can be flipped down to cover the keys in lineup to avoid visual disorientation in a pianist unfamiliar with the extended keyboard. On others, the colours of the extra white keys are reversed (black instead of white).