What stringed keyboard instrument did Leonardo da Vinci invent with a bowing wheel?

Leonardo da Vinci invented the viola organista, a stringed keyboard instrument played with a bowing wheel.

Leonardo sketched several versions of the instrument between the late 15th and early 16th centuries. Pressing keys caused strings to contact rotating wheels or a continuous bow, allowing sustained tones while the player used a keyboard.

The concept combined features of a keyboard and bowed string instrument. Unlike a harpsichord, whose strings are plucked, the viola organista was designed to produce sound through friction from a moving bowing mechanism.

Leonardo’s surviving drawings show designs rather than a confirmed original working instrument. Modern builders have constructed playable replicas, demonstrating how the mechanism could create a bowed-string sound.