The Risky Way Some Attackers Got Into Castles
Every castle required a means of disposing of human waste, and the solution — long, vertical shafts running down through the thickness of the wall to a moat, ditch, or river below — proved to have an unexpected, genuine security vulnerability.
Castle toilets, known as garderobes, were often constructed in small rooms set within the outer walls, sometimes in banks on several different floors and deliberately staggered so that one was not directly above another. The waste shafts angled down through the stonework and emptied out of an opening at the base of the wall, ideally located on the downwind side and falling into a moat, river, or ditch. It was a genuinely clever solution to a difficult engineering problem — until it was found that the same shaft could be used to allow a person to climb in.
Records show that it was not simply a theoretical risk: on more than one occasion, besieging forces had successfully penetrated a castle by having men climb up through the drainage shafts of its garderobes. As a result, the outside openings of these shafts were routinely fitted with iron grilles to prevent such an entrance. This was a security measure added to what was, on its face, purely a sanitation measure.
It is a nicely concrete illustration of how siege warfare influenced medieval castle design in ways that go well beyond the obvious — even the plumbing had to be built with an eye to keeping determined, unpleasant intruders out.
Step into 14th-century England—start reading The Draychester Chronicles today.