Leonardo da Vinci's viola organista combined a keyboard with rotating bows to imitate a string ensemble.
Leonardo designed the instrument in the late fifteenth century. Pressing keys caused strings to contact continuously rotating wheels or bows, allowing sustained sounds similar to those of bowed string instruments. The player could control several pitches from a keyboard rather than bowing each string by hand.
The viola organista reflects Leonardo's interest in combining mechanisms with music. His drawings explored different arrangements of strings, wheels, and keyboard controls. Unlike a normal keyboard instrument, it aimed to preserve the expressive quality of friction between a bow and a string.
No original Leonardo viola organista survives, and the instrument was not known to become a standard concert instrument. Modern makers have constructed working versions from his drawings, though interpretations differ because the sketches leave some details open.