A less obvious, but still typical feature of Portchester Castle is the plinth around the edges of the keep. It was a widely used technique called undermining that brought the plinth into a typical feature status. It was designed to stop attackers from standing with their backs to the walls where the archers inside the keep could not shoot at them as they dug underneath the wall to make it collapse. Due to the effectiveness of this offensive technique, plinths can be seen on nearly every square keep of every castle ever built. Although it is a different style of castle, Rochester Castle has a very similar keep and plinth to the one at Portchester, however Rochester is not similar in shape or size.
Atypical features are not quite as common at Portchester Castle, but are still present where an original part of the castle was needed to cater to its specific defensive needs.
Set within the bastion on the north wall there is a section that has been cut out where there is a smaller back entrance. This part of the wall is unique to the castle because the entrance lies directly underneath the castle’s latrines where as the attackers had easy access to the walls near the postern gate, they could also have human waste thrown down upon them. This was called a squinch and is a major atypical feature at Portchester. However this is not because of the feature itself, squinches were used as decorative pieces of architecture in medieval churches and were certainly widely used. The squinch at Portchester is atypical because it is placed within the walls of a castle and not as a decorative feature in a church.
Another atypical feature is not a defensive structure but a building designed for comfort. The parts of Richard II’s palace are typical for a palace but atypical for a castle. It was built in Portchester because of the lack of safety elsewhere, but also because the castle was becoming more domestic than defensive at the time and was not adapting to changes in technology unlike other castles that were making the appropriate changes to keep up with modern warfare at the time, such as the Tower of London. Later on, the reason for the castle becoming more domestic was more apparent after the castle lots its job as defender of the anchorage. Other castles in the area, unlike Portchester, would have had barely any facilities to house comforts because all the space would be taken up on defensive measures.
The last main atypical feature at Portchester is the actual positioning of the keep. Most castles during the medieval period would have the keep in the centre of their castles, or at the very least, in the centre of the inner bailey, unlike Portchester where the keep is in the very southwest corner. This is personalized to the area in which the castle lies because the keep was placed in a perfect vantage point that could see over the land of the area but over the sea and the harbour as well. It’s not difficult to spot the keep of Portchester Castle from any direction around the approaching lands. However, there is another factor for this original design. Because the keep is in the corner of the castle and merges with the curtain wall, there were less walls to build and maintain, making the castle overall cheaper, quicker and easier to construct.
I don’t believe it is possible to say whether Portchester is a typical or atypical medieval castle because every castle was unique in its own right, incorporating typical and atypical features to customise the stronghold to make it as effective as possible at defending the surrounding area. There were many reasons for customising a castle like: differing designs in architecture, the economy of the country or area, the types of warfare being used against a castle and the different owners of each castle wanting to use alternative defensive techniques. All of these can affect the types and amount of typical and atypical features that are used in any castle. This could therefore, give reason to the case that, generally there is no such thing as a ‘typical’ or ‘atypical’ castle.
