Precisely what professional activities Leonardo pursued in the mid to late 1480s in Milan, and how he kept his head financially above water, are questions that remain largely unexplained to this day. All we know for certain about this period is that it saw him designing war machines, some of them more fantastical than practical.

He also drew weapons of all different kinds, fortifications, complex defense systems, siege equipment, and more. Among the curiosities of this phase are heavily armored vehicles, whose immense weight would have all but prevented them from moving. Other ideas seem more immediately dangerous, such as his suggestion that the firepower of smaller cannon could be increased by using what was effectively grapeshot and an automated loading system. Positively gruesome are the horse-drawn chariots armored with scythes, with which the enemy could literally be mowed down. Leonardo copied at least one device of this kind from a contemporary military treatise, Roberto Valturio’s De re militari of 1472, and drew it several times. Not without irony, however, did he accompany his drawing with a warning that this kind of equipment could do just as much damage to one’s own troops as to those of the enemy. Read more