Which Leonardo da Vinci invention combined a keyboard with strings to imitate a violin?

Leonardo da Vinci’s viola organista combined a keyboard with strings to imitate the sound of bowed instruments.

The design appears in Leonardo’s notebooks and uses a keyboard to control strings that are rubbed by rotating wheels. Pressing keys would select notes while the wheel mechanism supplied the continuous friction normally produced by a bow.

Unlike a conventional piano, the viola organista was not based on hammers striking strings. Unlike an organ, it did not rely on pipes and air. Its purpose was to bring bowed-string characteristics into a keyboard instrument, an ambitious combination of mechanisms.

Leonardo’s surviving drawings show that he explored several related arrangements, but there is no reliable evidence that he completed a playable instrument. Modern builders have constructed versions from his plans, helping demonstrate the concept. The name is sometimes written with different capitalization, but “viola organista” is the standard term.