A Fantasy Writer’s Guide to Castles and Keeps: Part One

In this fantasy writing guide, we’re looking at the great, towering structures that dominate landscapes: castles and keeps. In exploring our past and learning about the foundations of the time periods fantasy draws upon, we can empower our writing with detail readers love. So In this guide, we’ll take a look at a medieval castle in fantasy or two, different fortifications, how they were overcome, and what life was like in a keep.

Medieval Castles In Fantasy

Fantasy is full of dramatic moments involving castles, keeps, and fortified cities. David Gemmell’s Legend tells the story of the siege of a city with the greatest defensive fortifications by the most powerful army in the land. Two of the most iconic battles in The Lord of the Rings series came in The Two Towers with Helms Deep and at Minas Tirith in The Return of the King. Fans of Game of Thrones will recall the Battle of Blackwater Bay and Daenerys’s conquest across the Narrow Sea.

It’s the author’s knowledge of these defensive structures and how they affect the course of battle which makes these moments so memorable. What challenges do the besiegers’ face? What steps must be taken to overcome those challenges? And what must the defenders do to resist, if anything at all?


The subject matter is quite large so this post will be the first in a short series. You can read the next parts of the guide by clicking below:

Click here to read Part Two (defensive features)

Click here to read Part Three (sieges)

A brief history

The Middles Ages lasted about a thousand years, kicking off in or around the 5th century and lasting until the 15th. It can be split into two periods: the ‘Dark Ages’, which ran from 5th to 10th century, and the High Middle Ages, from the 10th to 15th. (I understand the phrase Dark Ages is no longer accepted by some, but for ease, it’ll serve here).

Castles didn’t really exist in the Dark Ages. What did exist were the remains of Roman fortifications, but only in Western Europe. Everywhere else structures were made from wood.

Then the High Middle Ages came about and so too “The Age of Castles.” You couldn’t move for a castle in Europe. There were so many that no historian has been able to comprehensively document them all. Castles were status symbols, a means for the nobility to challenge their king, and incredibly, many continue to exist today.

Glossary of Fortifications

Before we hack our way further into this fantasy writing guide, it’d be useful to have a rundown of some of the different types of fortifications:

Castle: a fortification of the High Middle Ages, characterised by high walls with towers and usually a moat. Served both residential and/or administrative purposes.                                          

Fort: a small strongpoint occupied by military personnel.

Citadel: a word used to refer to either a castle or a fortified section within a city similar to a castle in size.

Fortress: also referred to as a fortified city or town, it has many features in common with a castle, such as high walls, gatehouses, and battlements, though much larger, housing a populace.

Motte and bailey: consisted of a tower standing upon a man-made mound, also known as a motte. This motte was located within a courtyard known as a bailey and encircled by a fence of wooden stakes (also known as a palisade) with a fortified gate.

Donjon: a great tower or innermost keep of a castle. The term donjon was later replaced with keep.

Rampart: a defensive wall of a castle or walled city, having a broad top with a walkway and typically a stone parapet.

Portcullis: a strong, heavy grating that can be lowered into grooves in the ground. Usually found in gatehouses.

In addition to these main types of fortification, there were tower houses, observation posts, and fortified churches and monasteries.

Early fortifications

Castles evolved out of early, cruder fortifications, three in particular: the gród, the bergfried, and the motte and bailey.

The gród was a simple, circular fortification that consisted of an earthen rampart with wooden walls, a fortified gate, and sometimes a moat. Something like this:


medieval castle in fantasy


The bergfried was a tower, used as a lookout and later as residences. Before the 13th century, they were mostly made of wood. Entrances to bergfrieds were found on the first floor instead of the ground floor. The reason? Bergfrieds and keeps tended to serve as the last point of defence and having it a floor higher made it more difficult for the enemy to take it.

The motte and bailey consisted of a wooden tower standing upon a man-made mound, also known as a motte. The motte was located within a courtyard known as a bailey, which itself was encircled by a fence of wooden stakes (also known as a palisade), with a fortified gate. It was a popular fortification with the Vikings. In the image below, the bailey is the lower level, the motte the upper.


motte and bailey.jpg


Motte and bailey



Towers played an integral role in the defence of a fortification. When constructed as part of the wall, they jutted forward to allow for flanking fire. They were also constructed separately. In the early years they were made from wood, later, stone.



A tower of Portchester castle

In most instances towers were placed at corners but were also added at intervals, sometimes at set distances, others random. It all depended on the terrain, available resources, and the skill of the builder. These factors also influenced the height of a tower.

A clever feature seen in some towers was an open back. Not only did it allow for supplies to easily be hauled up, but if attackers overran that tower, they couldn’t use it against the defenders. Some towers were cut off from the wall by drawbridges for added defence.

One vulnerability of towers was mining. Early towers were square in shape, but the dead angles made them vulnerable to mining attacks. In the 12th century, more circular or semi-circular towers were introduced. This was a risk the Romans were already aware of is why many Roman fortifications had D-shaped towers.

Lusk, dublin.jpg

Circular towers, Lusk, Dublin.

Gatehouses, moats, and drawbridges

The gate was perhaps the most important feature of a fortification because, in theory, it was the easiest point of access for attackers. Most gatehouses had battlements which defenders could stand upon to keep attackers at bay. Moats and drawbridges were added later to enhance defence.

Gatehouses consisted of a set of reinforced wooden and/or metal doors and a portcullis made of reinforced wood or iron. An example of a mighty gatehouse can be seen in Harlech Castle in Wales. It had three portcullises, three doors, and four towers. If you managed to get past the first you were trapped at the second, and so on. The walls of the gatehouse were punctuated with arrow slits through which the defenders could fire upon the attackers, and murder holes in the ceiling through which arrows could be fired, rocks dropped or hot liquids poured.

Harlech castle gatehouse

Harlech Castle gatehouse, Wales

One simple yet effective feature of gates was to place them at an angle instead of facing outwards. The purpose was to prevent battering rams from having a clear charge. Another feature designed with this in mind was the barbican, which was an outcropping of wall in front of the gatehouse.

Drawbridges were basic in construction, raised by chains and winches. They went hand in hand with moats, so if there was no moat, there was no drawbridge. The moat is one of the oldest features of fortifications. Simply put, it was a ditch surrounding the castle or keep. Rivers, lakes, ponds, or swamps were used to fill in moats, others were dry.


Dry moat of Dourdan Castle, France

A moat had to be deep enough to prevent an attacker from wading through it and wide enough to stop someone from leaping across. Around 3 meters, or 9 feet, was the average depth before the 11th century. After that, they grew much deeper. The size of the moat, however, depended on the terrain and how easily it could be excavated.

Moats were also reinforced with other obstructions, such as sharp stakes along the bottom or inner wall. A deep moat also protected against the threat of mining.


Caerphilly Castle, Wales

One thing about moats to keep in mind is that they tended to be disgusting. Excrement and waste from the fortification were tossed into the water, turning them into cesspools. It was the job of the peasantry to clean it up, on average twice per year. Peasants are always left with the shitty jobs, aren’t they?


Aerial shot of Bodiam Castle, East Sussex

Medieval Castle In Fantasy

We’ve spoken much about the medieval castle, but not much about fantasy castles. So in this section, we’re going to look at some awesome fantasy fortresses which may give you some ideas for your own writing. To discover more and to find all the credits for the images below, head over to my Pinterest page.

fantasy realm
fantasy realm
fantasy keep
fantasy keep
medieval fortress
medieval fortress
medieval castle in fantasy
medieval castle in fantasy
medieval castle fantasy
medieval castle fantasy

Get More Help With Your Fantasy Writing

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More Fantasy Writing Guides

Thank you for reading this fantasy writing guide on castles and keeps. The medieval fun isn’t over just yet, though. There are two more parts that complete the guide, which you can read by clicking below.

Click here to read Part Two (defensive features)

Click here to read Part Three (sieges)

If you’re looking for more fantasy writing guide, I have a few more that may be of interest to you:

Naming Fantasy Characters

A Fantasy Writers’ Guide to Weaponry

A Fantasy Writers’ Guide to Archery

A Fantasy Writers’ Guide to Armour.


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15 thoughts on “A Fantasy Writer’s Guide to Castles and Keeps: Part One

  1. Very informative.

    NOTE: I think, when you were describing the “gród” that you mean “encircling” rather than “circular” wall. “Circular” indicates a round shape, where “encircling” refers to enclosing or surrounding a space.

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