Shore up the defences, man the walls and get those supplies inside! Last time, we looked at siegecraft from the attackers’ side; this time, we’re on the defensive. There are a number of reasons why someone would choose to defend a specific location: to protect property or the lives of inhabitants; to secure a strategic location; to offset an opponent’s superior advantage; or because they have no other choice. While their reasoning may affect their tactical decisions, the manner in which they mount a defence will be based on a single goal: to keep the enemy at a distance while inflicting maximum damage on their forces.
To successfully defend a location against a determined attacker is a difficult proposition. Life under siege was gruelling and tense; living under the threat of attack, having to contend with dwindling supplies, panic in the populace, and the threat of disease could quickly wear down a defender’s moral. Bombardment from enemy artillery was often a constant threat, starting fires and damaging infrastructure, as was the potential for traitors to aid the attackers. Combine this with repeated attacks on the fortifications and waves of fresh troops seeking to overrun weary soldiers, and the defenders would find themselves hard pressed to stave off the enemy.
A defender would take every edge they could over their enemies, who were usually numerically superior. Some methods were brutal in the extreme, using terror to dissuade anyone attempting to breach the defences, while others made use of clever engineering to strengthen a position. The need for defence led to many new innovations as people sought to protect themselves in inventive ways.
YOU CALL THAT A WALL?
Walls are the most basic component of defence and a lot of effort and thought was put into their construction with numerous designs and developments over history. The protection and elevation they provided would allow the defender to engage their foes from a position of relative safety and provide a strong position to fight from as the enemy tried to gain access. Walls were costly to build and maintain, especially those large enough to protect a city, and would only be constructed if there was a high chance they would be needed.
While the architectural premise of a wall as a giant barrier remained unchanged, new developments led to additions being built into the structure to enhance its strength and the ability of soldiers to defend it. Narrow slits built into the structure called arrow loops were installed to allow archers to fire from the walls while the small opening reduced the accuracy of any return fire. While it restricted the potential for volley fire you could get from atop the walls, an archer could pick off targets with relative impunity. This technique was also used for the aptly named murder hole, which was a small opening in a passage or gateway through which the defenders could fire or pour harmful substances like boiling oil down on the attackers. The constant threat of such a fate was an incredible psychological deterrent that would make even the most determined attackers hesitate.
The upper battlements received a similar treatment, instead of being an unbroken line, the top of the wall was split with rectangular indentations called crenels in a saw-tooth pattern that provided a clear vantage point for defenders on the walls to fire from before ducking behind the stonework. This would be complimented by machicolations (essentially murder holes in the walls) punctuating the base of the parapet wall through which the defenders could drop rocks or more boiling oil on the besiegers. This combination of designs allowed a defending force to rain a hail of misery on an attacker as they were forced to cross a killing field and mount an assault, all in sight of the defenders weapons.
The structure of walls also improved as the sophistication of siege weapons developed. Soon it wasn’t enough to just be high; walls also had to be strong enough to withstand a punishing artillery barrage. The obvious answer was to make them thicker, but as weapons developed, and with the advent of gunpowder, architects were forced to develop new methods of defence. New designs featured walls and towers with curved sides (so an artillery shot might glance off) and were built around a core of compressed earth to absorb the energy of the impact.
GATES
The entrances to a city were a vital strategic point to both attacker and defender, far less solid than an unbroken wall, they were potential weak points and protected accordingly. Gatehouses were miniature forts built around an entrance and would often contain a small garrison in their own right, along with a slew of other protections like arrow loops and murder holes. The doors would be as strong as the defenders could make them, braced with extra supports to resist rams. Some more intricate gatehouses made use of a portcullis, a heavy metal grate that could be quickly lowered to secure the entrance. A complex system of winches and pulleys usually controlled the gate mechanism and it was important for the defences to guard against someone sabotaging them.
FROM THE GROUND UP
The design of the city or fort itself was often an integral part of the defence, architects would build a layered defence of inner walls and chokepoints that favoured a defender and forced an attacker to bleed for every inch. Mazes of walls and streets would confuse an aggressor, allowing the defender to launch attacks and lure them into traps. In many designs there would be a central keep which the defenders could fall back to as a last resort if the outer fortifications fell. This structure provided a last refuge and might allow them to hold if out if the enemy had exhausted itself on the assault.
Even the overall shape of the fortress could be a factor, designers would set towers and emplacements at crucial points to provide a bastion of strength as well as to ensure they had an overlapping arc of fire. The ideal was a “flankless fort” a structure with no unguarded sides and no clear approach for the enemy. With the advent of cannons the star shaped fort became popular as it would allow each spoke to provide supporting fire to those around it.
SUPPLIES
None of the most ingenious defences could protect from the needs of the people, having a supply of clean water and adequate supplies was of vital importance in a siege. Preferably a fort or city would have several deep wells (guarded against poisoning of course) and multiple storehouses to provide food to its populace. Some forts or cities might have the opportunity to resupply, especially if they were located on the coast where provisions could be delivered by ship, but in most circumstances a defender had to ration carefully if they wanted to outwait the besieger. A defender could easily have their hands full controlling a starving population while trying to fight off an army as food ran out.
ARTILLERY
The attackers aren’t the only ones who can throw rocks, larger forts and cities could have their own fixed siege machines built into the defences. Positioned to give the best line of sight, these constructs would benefit from enhanced elevation and stability, allowing them to launch heavy missiles at advancing foes, breaking up formations and destroying siege towers. A prepared defender would plot his ranges beforehand, using surrounding landmarks to improve his accuracy and gauge striking areas.
EXTERNAL DEFENSES
In an effort to resist attack some defenders would alter the land around their position to better serve their needs. Trenches were a cheap and effective way to stymie an enemy, while most could be overcome in time, they served to slow an advancing enemy and leave them at the mercy of fire from the defences. Trenches also made it difficult to move siege equipment like ladders and towers up to the walls and would have to be filled with earth or rock before the attackers could proceed. If the trench was deep enough it could be filled with water to make a moat, adding extra complexity to the process, not to mention a serious drowning risk for men wearing armour.
BY ANY MEANS
Stakes were high in a siege. When defeat may mean destruction of your home, there are few lengths people won’t go to. Aside from the horror of pouring flaming oil onto people, there were a number of traps and strategies a defender would use to survive an attack. Digging small pits was a common tactic – enough for a person to break their leg, or get stuck and be shot with an arrow – or setting booby traps inside the city for when the besiegers advanced. The attacking sappers often bore their fair share of these, having their tunnels flooded or filled with noxious smoke as the defenders tried to discourage any such attempt. A brave commander might even make use of sally ports and small sorties in an effort to destroy enemy siege engines or kill their general.
MAGIC
We talked about fantasy elements in the last article and the principles hold true for defenders too. Feel free to draw on your imagination, then think how it can affect your story. Perhaps your moat is not one of water but magical flames, and the defenders are trying to keep the spell secret from spies? Whatever you have, the attackers will try to find a way to beat it.
BREAK THEIR SPIRITS
A defender’s goal was to wear an attacker down, costing them as many men and materials as possible until they broke and left. They might only need to hold out for relief or they might need to drive them off on their own. In as much a psychological war as a physical one, a defender wants to make the thought of taking his position so horrifically ruinous to the attacker that the enemy deems it not worth the effort. Or they might weaken the besiegers enough that they can sally out and finish off the rest of the army.
The defensive methods I’ve covered are far from exhaustive, but should provide a foundation for writing this side of the siege, working together with the attackers’ techniques from the last article. With an understating of both sides you can write a more convincing ebb and flow of the battle, bringing it to life for your readers and making them believe in you work. Of course the focus should be on the drama and action of your story, but with this background knowledge you can better realise your ideas on the page. So grab your pen, get ready for a siege, and hold the line!
Richard Marpole
Jennie Ivins
Good article, but I always understood that curved towers were made because they were stronger against undermining (no weak corners), not because they deflect missiles better. Sharp, angled surfaces are better for that – see the sloping, angled walls of star forts, the point on “teardrop” donjons (like Chateau Gaillard) and even modern tank armour (not counting the Russians). Sometimes you had both, of course, with curved towers with an angled glacis at the foot (e.g. Krak des Chevaliers).
I think it varied a bit as people tried different methods to overcome the development and improvement of artillery and gunpowder weapons through time. Depending on construction methods and styles it would be common to see more traditional castles with tub-like cylindrical constructions for their towers because they offered a glancing surface to cannon shot. While star forts might have outworks which were more sharply angled to protect the inner walls called ravelins, think they might also have allowed the defenders a useful vantage point to fire on incoming forces. Different ways of trying to overcome the same problem.