Leonardo da Vinci designed the viola organista as a keyboard instrument with bowed strings.
Leonardo’s surviving drawings show a keyboard connected to strings that were sounded by a rotating wheel or belt. Pressing a key selected a string, while the moving bowing mechanism produced a sustained tone. The design combined features associated with the organ, keyboard instruments, and bowed string instruments.
The viola organista was never completed by Leonardo, so it is a design rather than a Renaissance commercial instrument. Several modern makers have built working reconstructions from his drawings, although details of the original mechanism remain open to interpretation. It is sometimes confused with the hurdy-gurdy, which also uses a wheel to bow strings, but the viola organista is played from a keyboard.