Artillery fire upon the besieged city. Warfare in the Middle Ages often centered upon the siege of a town or city delimited by walls, Battlements and towers. Concentric walls seen here, were an innovation brought back to Europe from the Middle East during the Crusades. Architects were forever in a race with the latest in cannon developments so as to transform cities and towns into impregnable fortresses.

In the early 15th century, the Italian architect Leon Battista Alberti suggested building castle walls in a zig-zag pattern like the teeth of a saw so as to better withstand artillery shells and to provide defenders with maximum advantage when repelling an enemy who had breached the walls. We see such a fortress wall design in this print. "The most effective way to protect walls against cannon fire proved to be depth (increasing the width of the defences) and angles (ensuring that attackers could only fire on walls at an oblique angle, not square on). Initially walls were lowered and backed, in front and behind, with earth. Towers were reformed into triangular bastions. This design matured into the trace italienne. Star-shaped fortresses surrounding towns and even cities with outlying defenses proved very difficult to capture, even for a well equipped army." At the end of the day, such sieges were successful or not to the extent that water and food supplies could be cut off from the city. Perhaps the critical variable was not the attacker's cannon or the defender's fortress but the cavalry employed by the besieged city whose critical mission was to foray at night for essential supplies.