What name is given to Leonardo da Vinci’s musical instrument played by friction wheels?

Leonardo da Vinci’s friction-wheel keyboard instrument is called the viola organista.

Leonardo designed the instrument in the late fifteenth century. It combined a keyboard with rotating wheels covered in horsehair or another rough material. When a key was pressed, a wheel contacted a string and made it vibrate, producing a sustained bowed-string sound.

The machine was inspired by instruments such as the hurdy-gurdy, but its keyboard layout made it closer in appearance to an organ or keyboard. Leonardo left drawings and notes rather than a surviving original instrument, so modern builders have reconstructed it from his designs.

The viola organista is not a normal viola and does not use a conventional bow. Its name reflects the intended combination of bowed-string timbre and keyboard control, which makes it one of Leonardo’s most unusual musical inventions.