What early mechanical device did Leonardo da Vinci design to make a carriage move without horses?

Leonardo da Vinci designed a self-propelled cart that could move without horses.

The machine used stored mechanical energy from springs rather than an animal, wind, or steam engine. A system of gears transferred the spring force to the wheels, and the front axle could be arranged to follow a predetermined path. This made the cart an early example of programmable mechanical motion.

The design is commonly dated to around 1478–1480 and may have been intended for stage effects or court entertainment. It was not a road vehicle for carrying passengers over long distances, and there is no evidence that Leonardo used it as ordinary transport.

Modern historians and engineers have debated whether the design was fully workable as drawn. Reconstructions show that its basic mechanism can function, but individual details require interpretation because Leonardo’s sketches are incomplete. The cart is also often confused with his armored fighting vehicle.