Which musical instrument did Leonardo da Vinci invent using a wheel to sound strings?

Leonardo da Vinci invented the viola organista, a keyboard instrument that uses a wheel to sound strings.

The instrument combines features of a keyboard and a bowed string instrument. Pressing keys moves strings against a rotating wheel, producing sustained tones in a way related to the action of a bow on a violin or viola.

Leonardo drew several versions of the idea in his notebooks, probably during the late 15th or early 16th century. He did not leave evidence of a surviving completed instrument, so the exact details of his intended mechanism are reconstructed from the drawings.

The viola organista is not a conventional organ and does not use pipes. It is also not simply a keyboard version of a harpsichord, whose strings are plucked. Modern builders have created playable reconstructions based on Leonardo’s sketches and related historical descriptions.