Which keyboard instrument did Leonardo da Vinci invent with strings and a bow?

Leonardo da Vinci invented the viola organista, a keyboard instrument played by strings and a bowing mechanism.

Leonardo drew several versions of the instrument in his notebooks. Pressing keys would activate strings, while rotating wheels or a continuous bow would make them sound. This combined the layout of a keyboard with the tone-production principle of bowed string instruments.

The viola organista was never built during Leonardo’s lifetime. Its design belongs to his broader interest in mechanical music, which also included drums, bells, and automated performance devices. The instrument is sometimes confused with the hurdy-gurdy, but a hurdy-gurdy uses a hand-turned wheel against strings, whereas Leonardo’s concept aimed to use keyboard control.

Modern makers have constructed playable interpretations from the surviving drawings. These reconstructions show that the design was technically ambitious, though its sound and operation depend on choices that Leonardo’s incomplete plans do not settle completely.