What musical instrument did Leonardo da Vinci design with strings, keys, and a bowing wheel?

Leonardo da Vinci designed the viola organista, an instrument with strings, keys, and a bowing wheel.

The viola organista combined features of a keyboard instrument and a bowed string instrument. Pressing keys selected strings, while a rotating wheel coated or covered with material rubbed against them to produce sound. Leonardo produced several drawings of related mechanisms, showing his interest in translating the expressive qualities of bowed strings into a keyboard format.

The design was never built by Leonardo, and surviving sketches vary in their details. Later instrument makers constructed working versions based on his plans and on modern interpretations of them. Those reconstructions demonstrate that the basic sound-producing principle can function, even though the exact historical instrument remains uncertain.

The name can cause confusion because the device is not simply a viola and not a conventional organ. It belongs to the broader history of mechanical and experimental musical instruments. Leonardo’s work connected artistic performance with his studies of friction, motion, strings, and mechanical control.