Anatomy of a Castle – The Moat

Moat from the gatehous

Moat from the gatehouse, Portchester Castle

There is, in my opinion, little to beat a moat for dramatic interest in a castle. The hero of one of my early novels swam a moat to get to his lady, an act which I now think would more likely lead to pneumonia than a happy ever after ending.

Failing pneumonia, he might have caught something else, since any latrines in the castle emptied into the moat. Castle wells had to be lined with lead to stop the contents of a moat seeping into them. In retrospect, having him come into contact with the moat at all seems like a bad idea.

Moats came in all shapes, sizes and locations: some are round; some are square; some are filled with water; some are empty; some are within the outer walls and some are outside the walls.

This is probably the most famous moat in England. It’s Bodiam Castle in East Sussex. On a still day the castle is reflected in the moat, reminding the visitor that Bodiam wasn’t built for defensive purposes, but simply to be beautiful.


By Pilgrimsoldier – Own work, CC BY-SA 3.0,

Most moats added to the castle’s defences. It was almost impossible to storm a castle with a moat. They made it difficult to get siege engines close. Although few moats were as wide as Bodiam’s, you could see that there would be no chance of soldiers getting close to the walls in any kind of siege tower. There’s nowhere to rest a ladder for soldiers to climb to the top of the walls. Even more important, the towers couldn’t be mined.

Mining was the process by which the besieging army dug underground until they were beneath a corner of a tower. Once there they would set a fire which caused part of the wall to collapse. The army would then enter the castle through the damaged wall.

The moat at Old Sarum is empty, but the sides of the hill on which the castle was built are very steep. Although the moat encircles the walls, the castle’s outer bailey is on the other side of the moat. In the photograph below the outer bailey is where there are people walking.

Moat, Old Sarum (2)

Moat, Old Sarum

Attacking from below was never a great option for a medieval soldier and attacking up a steep hill was even worse. It was easy for people above to throw things down on them and there was little they could do to protect themselves.

Here’s another photograph from Old Sarum down into the valley. You can see how high and steep the hill is.

Moat and outer bailey, Old Sarum

Moat and outer bailey, Old Sarum

Portchester Castle is one that has a water moat. It’s not terribly impressive these days. As you can see in the picture below, part of it is within the outer walls and there are people having their lunch in the outer bailey.  That part of the outer bailey alone is large enough to host a cricket match. What you can’t see from the photograph is that the moat goes outside the outer walls as well.

Moat and outer bailey

Moat and outer bailey, Portchester Castle

You’ll remember from last week’s post that Portchester Castle is on the edge of a harbour, so there’s plenty of water about for the moat. In the Middle Ages the moat would have been deeper and wider and much more of an obstacle to anyone who wanted to storm the castle.

Bodiam had a fairly large moat, but Kenilworth Castle’s moat was huge. It was created by damming two rivers, and the castle was effectively surrounded by a lake. These water defences were partly responsible for the longest siege in England in the Middle Ages.  For six months in 1266 the castle held out against Henry III and his army. Attempts to storm the castle by water failed. His stone-throwing weapons did not have the range of those within the castle walls. In the end, the inhabitants of the castle surrendered because they were running out of food.



Castle – Marc Morris

Portchester Castle –  John Goodall


April Munday is the author of the Soldiers of Fortune and Regency Spies series of novels, as well as standalone novels set in the fourteenth century.

Available now:













Filed under Castle

16 responses to “Anatomy of a Castle – The Moat

  1. Losing the Plot

    I worked in Carrickfergus Castle for a while, it didn’t have a moat, but was surrounded by the sea on three sides. It was seiged on a few occasions, most horribly by Edward the Bruce, brother of Robert, but the walls held


  2. Would love to photograph Bodiam castle with the reflection even though everyone and his dog has done it!

    Liked by 2 people

  3. Stunning images. I am enjoying this series very much. Thanks!

    Liked by 2 people

  4. Always loved Leeds Castle in Kent. But it was built on islands in a small lake, so perhaps the moat classification doesn’t fit. But it sure is pretty!

    Moats that had a current were much cleaner than those created by stagnant, dammed water. Understand dredging was a constant concern, as moats tended to be about as shallow as an 18th century canal bed, which also needed dredging & suffered many of the same issues. Bet muckraking was an odious task! Maybe prisoners were made to do it. But as valuables might be found, some may have weighed the risks & went for it.

    Moats with currents were from diverted waterways with a strong enough sweep to flush things along. All man-made diking of moats were prone to washouts in heavy rains or spring runoffs. Little was known of planting deep-rooting vegetation to steady the berms. Besides, vegetation could conceal enemies.

    Dry moats made more sense, but as you pointed out, sappers could more easily mine under castles from dry moats than from watered ones.

    But, oh, the effect! Perhaps your early hero lucked out & found a cleaner moat to perform his derring-do. Some did exist, so since he’s your protagonist, I’ll be happy to believe he didn’t swim through muck

    Have a great week!

    Liked by 1 person

    • Thank you. I wasn’t very far from Leeds Castle today, but I don’t think my driver would have appreciated the diversion to allow me to go and visit it.

      We’re having very pleasant weather at the moment, so I should probably go out and visit a few more castles before autumn is upon us.

      I’m hoping to be back in Kent before winter, so I might be able to visit Leeds and Rochester Castles this year.

      Liked by 1 person

  5. Moats are wonderful. When I was a child it was my ambition to live somewhere with a moat. My mother used to say, “Very damp and smelly.”

    Liked by 1 person

  6. I am really enjoying this series April!

    Rachael |

    Liked by 1 person

  7. Pingback: Anatomy of a Castle | A Writer's Perspective

Please join the conversation

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s