This drawing is the most formal of Leonardo’s military drawings from the period, its composition derived from a woodcut in Valturio showing a framework and pulley for hoisting a cannon on and off its bogey. The scene appears to be a military storeyard or arsenal with teams of nude men struggling with levers to take the weight of an enormous bombard, closely resembling the siege bombards that were a speciality of Ottoman foundries, such as the ‘Dardanelles Gun’ now at Fort Nelson, Portsmouth (and Leonardo has hardly exaggerated the size). Beyond are more gun barrels lying beneath a pitched roof against the wall of a fortress, with huge stone cannonballs, a mortar, ladders and lances. Melzi