A Moat and the Tunnel

Winter                                   Waning Moon of Long Nights

As any docent or academic knows, you learn strange things when you wander around in a new subject or when returning to an old one.  Castles, an ongoing fascination for me since I was a boy, have come up in this new book I’m writing.  As I launched myself into the names of things, e.g. machicolations (holes in a parapet through which rocks and boiling oil could be dropped on attackers), barbicans, portcullis and curtain wall, I came across the old familiar moat.

As in the picture, a moat is a water-filled trench around the outside of a castle.  Like you, I thought the moat offered an additional circle of protection for the outside of the castle, a wet barrier.  Not primarily.  Turns out that siege techniques grew very sophisticated and common protocol including tunneling under a castle’s curtain wall or one of its square sided towers (if such existed) and digging a deeper hole, then blowing it out with explosives or just letting it collapse under its own weight.   This effected an entry to the castle through its most imposing feature, the sheer rock sides.

The moat put a stop to that because any tunnel underneath it would collapse and fill in with water.  A definite deterrent.