Leonardo da Vinci designed the viola organista, a keyboard instrument that combined features of a piano and a bowed string instrument.
Leonardo described the machine in his notebooks around 1488–1490. Pressing keys caused a continuous belt or set of wheels to rub against strings, producing sound in a way broadly comparable to a violin bow. The performer could therefore play bowed strings from a keyboard rather than using a separate bow for each note.
The viola organista was never built by Leonardo, and surviving drawings show more than one possible mechanism. It is often confused with the hurdy-gurdy, which uses a hand-turned wheel and stopped strings, whereas Leonardo’s concept was intended to use a keyboard.
Several modern builders have reconstructed versions from Leonardo’s drawings. The instrument is important because it shows his interest in combining mechanical engineering with musical design, not because it became a standard Renaissance instrument.