Shell Keep
A shell keep is a distinctive type of medieval fortification that was particularly prominent in the United Kingdom during the 12th century. These structures are characterized by their unique architectural style, typically involving a stone structure built around the top of a motte – a raised earthwork forming part of a traditional motte-and-bailey castle.
Architectural Features
Shell keeps are essentially circular or sometimes polygonal stone walls that enclose the top of a motte. They often replaced earlier wooden keeps, providing increased defensive capabilities. A shell keep does not have a roof or internal structures, instead serving as an outer wall around which buildings could be constructed, such as residential quarters, stores, and chapels.
The walls of a shell keep could be reinforced with buttresses and topped with battlements, allowing defenders to fire upon attackers. Access to the shell keep was often through a gatehouse, which could be fortified to withstand sieges.
Historical Examples
Several notable examples of shell keeps exist, each showcasing variations in design and historical context:
-
Restormel Castle in Cornwall is a well-preserved example of a circular shell keep. Its design showcases the typical construction with a high circular wall enclosing an open space.
-
Farnham Castle in Surrey features a shell keep built atop a massive Norman foundation, illustrating the transition from timber to stone fortifications.
-
Cardiff Castle in Wales is another example where the original wooden motte-and-bailey design was upgraded to a stone shell keep, providing a robust defensive structure.
-
Urquhart Castle on Loch Ness in Scotland includes remnants of what is thought to be a shell keep, adding to its strategic location and historical significance.
Evolution and Significance
The shell keep represented an evolution from earlier motte-and-bailey designs, reflecting advancements in military architecture and the need for stronger fortifications. As siege warfare techniques evolved, the shortcomings of wooden structures became apparent, prompting the development of more durable and defensible stone keeps.
By the 15th century, the term "shell keep" was widely used, and these structures had become a common feature in castles across the British Isles. However, as military technology continued to advance, many shell keeps were modified or replaced by more modern defensive structures, such as concentric castles.