What bowed-string keyboard instrument did Leonardo da Vinci invent?

Leonardo da Vinci invented the viola organista, a keyboard instrument played with bowed strings.

Leonardo sketched several versions of the instrument between the late fifteenth and early sixteenth centuries. Pressing keys selected strings, while a rotating mechanism rubbed the strings with a continuous bowing surface. This combined the keyboard’s ability to select notes with the sustained sound of bowed instruments.

Unlike a conventional piano, the viola organista does not strike strings with hammers. It is also different from a hurdy-gurdy, whose strings are sounded by a wheel but whose notes are normally stopped by a hand-operated key or keyboard mechanism. Leonardo’s design was never produced as a standard historical instrument.

Modern builders have reconstructed versions from his drawings. These instruments demonstrate the concept, but details vary because Leonardo left multiple designs rather than one final, fully specified model.