What Leonardo da Vinci invention combined a keyboard with a bowed string mechanism?

Leonardo da Vinci’s keyboard instrument with a bowed string mechanism was the viola organista.

Leonardo drew several versions of the instrument during the late fifteenth and early sixteenth centuries. Pressing keys selected strings, while a rotating wheel or wheels rubbed against them to produce a sustained sound. In concept, it combined the keyboard of an organ or piano with the continuous tone of a bowed string instrument.

The viola organista was never built by Leonardo, and no single final design exists. His sketches show changing arrangements, including systems using friction wheels and multiple strings. The instrument therefore represents a family of related proposals rather than one standardized historical model.

Modern builders have constructed playable versions from the drawings. The name can cause confusion because it sounds like an ordinary viola, but Leonardo’s design was a keyboard-controlled machine. Its significance is the unusual attempt to automate bowing while preserving the expressive quality of string sound.