What type of vehicle did Leonardo da Vinci sketch as a protected military machine?

Leonardo da Vinci sketched an armored vehicle as a protected military machine.

The design appeared in his notebooks around 1487–1489 and resembled a conical, turtle-like platform covered with armor plates. Its sloping surfaces were intended to deflect enemy fire, while weapons mounted around the perimeter could provide all-round defense.

Leonardo’s drawing shows the vehicle being driven by cranks connected to internal gears. Historians and engineers have noted that the mechanism, as drawn, would not move correctly because of a gear arrangement that appears to make the machine run backward. Some reconstructions correct this apparent flaw.

The vehicle is commonly described as an early tank concept, but it was never built for Renaissance warfare. The modern word “tank” belongs to twentieth-century armored warfare; “armored vehicle” is the more precise description of Leonardo’s proposed machine.