Who hasn’t built a sandcastle on a beach? Well, if you’re like me, when you do, you dig out a circle and pile the sand high, then when the tide rises, you watch the little circular ditch fill with water. Eventually, the castle disintegrates, eroded by the waves.
When the Normans brought along their motte and bailey design, it seemed natural it would evolve into something else. As the labourers dug, creating the motte, they left behind a defensive ditch. Sometimes left dry, by the 12th century it was more common for it to be filled with water from nearby rivers. The word moat is derived from the French word motte.
The depth and width of the moat acted as a deterrent both to anyone willing to swim across or prepared to mine the walls. A besieger would be a sitting duck as he attempted to cross the moat.
By the time castles passed out of fashion as military fortresses, the moat had turned into a fashionable accessory for palaces or manor houses. Most of these moats are shallow and only useful for keeping fishes and swans.
Here’s an evolution in pictures