Leonardo da Vinci designed the viola organista, a keyboard instrument intended to produce bowed-string sounds. Its keyboard controlled rotating wheels or ribbons that rubbed against strings, combining features of a viola with keyboard operation.
Leonardo drew several versions of the instrument during the late fifteenth and early sixteenth centuries. Pressing a key selected a string, while a mechanism brought a continuously moving friction surface into contact with it. This allowed a player to create sustained tones without directly bowing each string.
The viola organista was never known to have been completed by Leonardo himself. Modern makers have constructed playable interpretations from his sketches, but the surviving drawings show evolving ideas rather than one finalized blueprint.
It is often confused with the organ, harpsichord, or hurdy-gurdy. Unlike those instruments, Leonardo’s concept specifically used a keyboard to activate bowed strings.