Medieval castle architecture is the design of fortified residences and strongholds built in the Middle Ages. Castles combined defence with everyday life: walls, gates and towers controlled access, while halls, chambers, kitchens and storage areas supported the people who lived or worked inside. Their forms varied by region, date, terrain and purpose, so no single plan represents every castle.
Features at a glance
| Feature | What to look for | Main function |
|---|---|---|
| Motte and bailey | An earth mound beside an enclosed courtyard | Raised defence and a protected working or living area |
| Curtain wall | A substantial wall enclosing part or all of the site | Boundary, protection and controlled movement |
| Keep | A large fortified building, often placed within the enclosure | Residence, administration, refuge or a combination of these |
| Tower | A projecting or attached high structure | Observation, defence and sometimes accommodation |
| Gatehouse | A defended entrance, sometimes with one or two towers | Regulating entry and protecting the approach |
| Moat | A ditch, often associated with an entrance or wall | Making approach more difficult and marking the boundary |
Walls, towers and entrances
Curtain walls
A curtain wall is the enclosing wall between towers or other strong points. It could be the principal defence, but its height and thickness differed between sites. Look for wall-walks, openings and changes in masonry that may show later rebuilding. Some castles had substantial walls without a separate keep.
Towers
Towers gave defenders a higher viewpoint and could project beyond a wall, improving the view along its face and the ability to respond to an approach. They might be round, square or another shape. A tower was not necessarily only a fighting position: some contained chambers or other working spaces.
Gatehouses, bridges and moats
The gate was a controlled passage rather than just a gap in the wall. Gatehouses could develop from simple arched entrances into larger structures with towers, gates and portcullises. A drawbridge might cross a moat or ditch, but not every castle had a moat, and surviving arrangements can be difficult to interpret.
Battlements
Battlements are the alternating raised sections and gaps along the top of a defensive wall or tower. They offered cover and openings from which defenders could observe or act. English Heritage describes the former crenellated curtain wall at Stokesay Castle; surviving walls and later rebuilding need to be read in their local context.
Living inside the castle
A castle needed rooms for eating, sleeping, administration and storage. The great hall was commonly a major communal room for meals and public business. A private chamber, sometimes called a solar, offered more domestic privacy. Kitchens, chapels and undercrofts also formed part of castle life. These spaces remind us that castles were residences and administrative centres as well as fortifications.
Keeps and changing designs
A keep is a large fortified building, but it was not a required feature. Some castles had one; others relied on walls, towers or earthworks. Welsh castles show several approaches, including earth-and-timber motte-and-bailey sites, ringworks and castles built or rebuilt in stone. Designs also changed over time, sometimes through several building phases rather than one complete plan.
Three examples to recognise
Eynsford Castle, Kent
Eynsford Castle was a Norman castle with neither a motte nor a keep. Its curtain wall formed the principal defence. The entrance was reached across a wide, shallow moat by a timber drawbridge. Inside, the hall served eating and public business, while a solar provided a domestic chamber and undercrofts supplied storage or residential space.
Middleham Castle, Yorkshire
Middleham Castle developed through building phases from the twelfth to the fifteenth centuries. Its late-twelfth-century keep stood within later arrangements that included a curtain wall, towers and more comfortable chambers. The castle contained a great hall, private chamber, chapel, kitchen and storage areas. Its history shows that defensive and domestic features could be planned together and altered over time.
Caerphilly and Chepstow
Cadw’s account of Welsh castles describes Caerphilly as among the first planned concentric castles, with nested defensive enclosures. It also identifies Chepstow as an early stone castle. Welsh examples demonstrate that castles could begin in earth and timber, be rebuilt in stone, or use stone from the start.
Compact glossary
- Bailey: An enclosed courtyard or ward.
- Concentric castle: A castle with one defensive enclosure inside another.
- Keep: A large fortified building within a castle.
- Moat: A ditch, sometimes water-filled, beside a defence.
- Portcullis: A vertically sliding gate.
- Ringwork: An earthwork enclosure, usually bounded by a bank and ditch.
- Solar: A private domestic chamber, often associated with a hall.
Frequently asked questions
Did every medieval castle have a keep?
No. Some castles, including Eynsford, relied on walls and other arrangements without a keep.
Was a castle mainly a military building?
No. Defence was important, but castles also contained halls, chambers, kitchens, chapels and storage spaces.
Did all castles develop in the same order?
No. Castle designs varied by place, purpose and period, and many sites were altered through several building phases.
Sources checked 7 October 2026: English Heritage descriptions of Eynsford Castle and Middleham Castle; Cadw, “Castles of Wales”; English Heritage, Stokesay Castle teachers’ kit.
