Which Leonardo da Vinci design combined a bowed string instrument with keyboard-style keys?

Leonardo da Vinci’s viola organista combined bowed strings with keyboard-style keys.

Leonardo developed the idea in sketches made during the late fifteenth and early sixteenth centuries. Pressing a key was intended to move a bow or a continuous bowing mechanism against strings, allowing the performer to control pitch from a keyboard while producing a sustained string sound.

Unlike a conventional piano, the instrument did not strike strings with hammers. Unlike a normal violin, the player did not draw a handheld bow across the strings. Leonardo never completed a surviving original instrument, but modern makers have built working versions based on his drawings. The design demonstrates his interest in merging familiar mechanical systems into new musical instruments.