During the 1480s Leonardo lived in Milan, Italy’s leading centre of arms manufacture. His many military drawings of the period suggest that he dallied with the idea of writing a treatise on weaponry, to which this drawing may have been envisaged as an illustration. Teams of nude men struggle to take the weight of an enormous siege cannon, of a type that was then a speciality of eastern European and Ottoman foundries, weighing many tons and firing huge stone cannonballs.

No. 4