"I shall make covered chariots, that are safe and cannot be assaulted; cars which fear no great numbers when breaking through the ranks of the enemy and its artillery. Behind them, the infantrymen shall follow, without fearing injury or other impediments"
Leonardo's idea of sowing panic and destruction among the enemy troops
was embodied in his design of a tortoise-shaped car, reinforced with
metal plates, with an inner turret and armed with guns. The car was
to be operated from inside by 8 men, who would turn the cranks to move
the wheels. The notes on the drawing show that Leonardo had thought
of replacing the men with horses, although he was soon turned off the
idea by the thought that the animals might become restive in such a
narrow and noisy environment. The firing direction would be decided
by the men in the upper part of the car, from where they could see the
battlefield through slits or portholes.
Codex Arundel, sheet 1030