Leonardo da Vinci designed the viola organista, a keyboard instrument intended to produce bowed-string sounds.
The player would press keys like those of an organ or piano. Inside the instrument, a rotating wheel or set of wheels would rub against strings, functioning like the bow of a string instrument. This allowed a keyboard player to control pitch while producing a sustained bowed tone.
Leonardo’s surviving sketches show more than one version of the concept. The instrument was never built during his lifetime, but later makers constructed working interpretations from his drawings. These reconstructions demonstrate that the idea can produce sound, although they do not prove that Leonardo completed a playable original.
The viola organista is not a conventional viola and is not simply an organ. It combines keyboard control with bowed strings, making it an unusual hybrid instrument.