What Leonardo da Vinci invention was a four-wheeled self-propelled cart?

Leonardo da Vinci’s self-propelled cart was a four-wheeled mechanical vehicle designed to move without an animal pulling it.

Leonardo’s drawing, usually dated to the late fifteenth century, shows a cart driven by coiled springs. The springs stored energy, while a system of gears transferred that energy to the wheels. Steering could be set in advance, allowing the cart to follow a predetermined route.

Because the mechanism was powered by springs rather than an engine, it was not an automobile in the modern sense. It was closer to a large clockwork machine. The design may have been intended for theatrical performances or ceremonial events at an Italian court.

A reconstruction made for a 2006 exhibition demonstrated that the basic mechanism could work. The cart is sometimes called the first self-propelled vehicle, although that label depends on how broadly “vehicle” and “self-propelled” are defined.