What Renaissance string instrument did Leonardo da Vinci design with a keyboard?

Leonardo da Vinci designed the viola organista, a keyboard-controlled string instrument.

Leonardo sketched the instrument in the late 15th century, combining features of a keyboard with the bowed-string principle of instruments such as the viola. Pressing keys would move small mechanisms so that rotating wheels or bows rubbed against strings, producing sustained tones.

Unlike a piano, the viola organista was not based on hammers striking strings. Unlike an ordinary organ, it did not produce sound through pipes. Its unusual design reflects Leonardo’s interest in translating one kind of motion into another.

The instrument was never built by Leonardo in a surviving, fully documented form. Modern makers have reconstructed versions from his drawings, but those reconstructions should not be confused with an original Renaissance instrument.