What Leonardo da Vinci invention combined features of a violin and a keyboard?

Leonardo da Vinci’s viola organista was a keyboard instrument that produced string sounds through a continuously moving wheel.

Leonardo developed several versions of the idea during the late fifteenth and early sixteenth centuries. Pressing keys caused strings to touch a rotating wheel, much as a bow causes a violin string to vibrate. The player could therefore control pitch with a keyboard while obtaining a sustained bowed-string tone.

The instrument was never built during Leonardo’s lifetime, and his surviving drawings show evolving concepts rather than one finalized model. It is commonly described as combining the functions of a keyboard and a bowed string instrument. Its name refers to the viola family, although it does not operate like a conventional violin.

Modern builders have constructed playable versions from Leonardo’s plans. The viola organista should not be confused with an ordinary organ: its sound comes from vibrating strings, not from air passing through pipes. It also differs from a piano, whose hammers strike strings instead of rubbing them with a wheel.