Leonardo da Vinci designed the viola organista, a keyboard instrument with bowed strings.
The viola organista combined a keyboard with a set of strings and rotating wheels or bows. Pressing keys would bring the strings into contact with the moving bowing mechanism, producing a sustained sound more like that of a viola or other bowed instrument than a conventional plucked keyboard instrument.
Leonardo drew several versions of the concept in his notebooks. The instrument shows his interest in translating one kind of human action into another: the performer used familiar keyboard keys, while the mechanism supplied the continuous bowing. It was an inventive proposal rather than a standard Renaissance instrument.
The viola organista should not be confused with the piano. A piano produces sound by hammers striking strings, while Leonardo’s design relied on friction from moving bows or wheels. Modern reconstructions have demonstrated that the idea can produce music, but no authenticated original instrument made by Leonardo is known.