Leonardo da Vinci designed the viola organista as a keyboard instrument whose strings were sounded by rotating, rosined wheels or bows.
The design appears in Leonardo’s notebooks from the late 15th or early 16th century. Pressing keys would select strings while a crank turned the friction mechanism, combining keyboard control with the sustained sound of bowed strings.
The viola organista was never built by Leonardo, so it is best described as a proposed or designed instrument rather than a completed invention. Modern makers have reconstructed versions from his drawings.
It is often confused with the hurdy-gurdy because both use a rotating wheel, but the viola organista was conceived as a keyboard instrument and used multiple bowed strings.