Leonardo da Vinci invented the viola organista, a keyboard instrument with continuously bowed strings.
Leonardo included several versions of the idea in his notebooks during the late fifteenth and early sixteenth centuries. Pressing a key would move a string against a rotating wheel or belt, producing a sustained sound. The concept combined the keyboard layout of an organ or harpsichord with the bowed tone of string instruments.
Unlike a conventional violin, the performer did not use a bow held in the hand. A crank or other mechanism kept the bowing surface moving while the keyboard selected the notes. Leonardo never produced a surviving, fully documented original instrument.
The instrument’s name is modern and reflects its hybrid character. It should not be confused with an ordinary viola, which is played with a handheld bow. Several modern builders have made playable reconstructions from Leonardo’s drawings, but these are later interpretations rather than surviving Renaissance instruments.