What Leonardo da Vinci musical invention combined a keyboard with bowed strings?

Leonardo da Vinci’s keyboard instrument with bowed strings is called the viola organista.

Leonardo designed the instrument during the 15th century, combining the keyboard layout of an organ or keyboard instrument with the sound-producing principle of bowed strings. Pressing keys would bring strings into contact with rotating wheels or a continuous bowing mechanism, allowing sustained tones.

The viola organista was never completed by Leonardo, and no surviving original instrument is known. Its drawings appear in Leonardo’s notebooks, including the Codex Atlanticus. The design reflects his interest in adapting mechanical systems to musical performance rather than simply copying an existing instrument.

Several modern makers have built experimental reconstructions. These instruments differ in their details because Leonardo’s sketches leave room for interpretation. The viola organista should not be confused with a standard viola, which is played with a handheld bow, or with a hurdy-gurdy, whose strings are sounded by a wheel but are not controlled by a piano-style keyboard in the same way.