It is not known exactly when Cristofori first built a piano. An inventory made by his employers, the Medici family, indicates the existence of a piano by the year 1700; another document of doubtful authenticity indicates a date of 1698.[citation needed] The three Cristofori pianos that survive today date from the 1720s.[citation needed]
With the advent of powerful desktop computers, highly realistic sampled digital grand pianos have become available as affordable software modules. Some use multi-gigabyte piano sample sets with as many as 90 recordings, each lasting many seconds, for each of the 88 keys under different conditions, augmented by additional samples to emulate sympathetic resonance, key release, the drop of the dampers, and simulations of piano techniques like re-pedaling.
