Leonardo da Vinci designed the viola organista, a keyboard machine that plays strings with rotating bows.
Leonardo developed the concept in drawings from the late 15th and early 16th centuries. Pressing keys would select strings, while a continuous belt or wheel carrying bows would rub them and produce sound. The design combined the expressive principle of bowed instruments with the control system of a keyboard.
The viola organista was not a standard instrument made and used by Leonardo. Several modern builders have reconstructed versions from his drawings, and these instruments can produce bowed-string sounds. It is therefore best understood as an experimental musical invention rather than an ancestor of the piano.
The name can cause confusion because the machine is not simply a viola with keys. Its unusual mechanism is what makes the design historically important: it sought to let one performer control sustained, bow-like tones across many pitches.