What organ-like keyboard instrument did Leonardo da Vinci design with continuous strings?

Leonardo da Vinci designed the viola organista, an organ-like keyboard instrument with continuous strings.

Leonardo’s sketches show a keyboard controlling strings that are sounded by friction from rotating wheels or bows. Pressing keys would select notes while the moving mechanism rubbed the strings, producing a sustained sound. The design combined features associated with bowed string instruments and keyboard instruments.

Leonardo worked on versions of the idea during the late fifteenth and early sixteenth centuries. Unlike a conventional pipe organ, the instrument did not depend on ranks of pipes. Unlike a harpsichord, it was not based on plucking strings. Its unusual mechanism made it a striking example of Leonardo’s attempts to automate musical performance.

The viola organista was not known to have been completed by Leonardo. Modern reconstructions have been built from his drawings, including an instrument made by Polish musician and builder Sławomir Zubrzycki, which was presented publicly in 2013. The name is modern, but it reflects the design’s hybrid character.