What musical instrument did Leonardo da Vinci invent using a keyboard and a bow mechanism?

Leonardo da Vinci invented the viola organista, a keyboard instrument that uses a bow mechanism to sound strings.

Leonardo sketched several versions of the instrument during the late 15th and early 16th centuries. Pressing keys selected strings, while rotating wheels or a continuous bowing surface rubbed the strings to produce sound. The design combined features associated with keyboard instruments and bowed string instruments.

The viola organista was never built by Leonardo and appears to have remained a series of experimental drawings. It is sometimes confused with a hurdy-gurdy, but the two instruments differ: a hurdy-gurdy uses a hand-turned wheel and stopped strings, while Leonardo’s design uses a keyboard to control the notes.

Modern makers have constructed playable interpretations from the surviving sketches. These reconstructions show how Leonardo’s interest in mechanics extended beyond machines for war, transport, and flight into musical engineering.