Leonardo da Vinci designed the viola organista, a keyboard instrument intended to produce bowed-string sounds continuously.
The instrument combines a keyboard with rotating wheels or a belt that rub against strings, somewhat like a group of bowed string instruments operated by one performer. Pressing keys selects the pitches while the mechanical system provides the friction needed to sound the strings.
Leonardo drew several versions of the idea in his notebooks, but no completed instrument made by him is known. The viola organista is therefore best understood as a documented design rather than a successful Renaissance product. It also differs from a harpsichord, whose strings are plucked, and a clavichord, whose strings are struck.
Builders have created modern reconstructions based on Leonardo’s drawings. Those reconstructions demonstrate the musical potential of the concept while also showing why the mechanism required careful engineering to control tuning, pressure, and sustained sound.