This is probably the most controversial and mysterious Leonardo drawing that has been discussed since its discovery, which took place in a fortuitous and unexpected way, between 1966 and 1968, in the laboratory of restoration of ancient books of the Esarchico Monastery of Santa Maria di Grottaferrata (Rome).

This is not a completely new invention, but the optimization of an existing weapon. In fact, at the time of Leonardo bombards were used in sieges. Their large mouth allowed them to fire large bullets that could easily open large breaches in enemy defenses. However, the machines were very heavy and took a long time to maneuver.