Leonardo da Vinci designed the viola organista by combining a keyboard with bowed strings.
The instrument used keys to control strings while a rotating mechanism supplied the continuous friction normally produced by a bow. Leonardo drew several versions of the idea, including one in the Codex Atlanticus. The design aimed to produce sustained, expressive tones while retaining the layout and controllability of a keyboard instrument.
No surviving evidence shows that Leonardo completed a working viola organista. Modern builders have created playable reconstructions from his drawings, although the exact sound and mechanism Leonardo intended remain uncertain. The name is a modern description of the instrument’s hybrid character rather than a documented name Leonardo necessarily used.
The viola organista should not be confused with the organ. Unlike a pipe organ, it does not produce sound through air pipes. Its important innovation was mechanical: keyboard action controlled the contact between strings and a moving bowing surface.