What instrument did Leonardo da Vinci design with a keyboard and strings rubbed by wheels?

Leonardo da Vinci designed the viola organista, a keyboard instrument with strings rubbed by rotating wheels.

Leonardo explored the idea in notebooks during the late fifteenth century. The instrument combined the keyboard layout of an organ or keyboard instrument with the sound-producing principle of a bowed string instrument. Pressing a key would bring a string into contact with a rotating wheel, creating sustained tones as the wheel moved.

Unlike a conventional piano, the strings were not struck by hammers. Unlike a typical violin, they did not need a bow held directly by a player. Leonardo produced several versions of the concept, but no surviving Renaissance instrument proves that he completed a working model.

The name viola organista reflects the hybrid design: “viola” points to bowed strings, while “organista” points to keyboard operation. Modern builders have constructed playable reconstructions based on Leonardo’s drawings.