Fortified tower
A fortified tower, commonly known as a keep in English contexts or donjon in French, is a tall, heavily defended stone structure that forms the core of medieval European castles, functioning as both a residence for nobility and the ultimate stronghold during sieges.[1] These towers emerged in the 11th and 12th centuries as fortifications evolved from earlier wooden motte-and-bailey designs, responding to the threats of feudal warfare and the collapse of centralized authority after the Carolingian Empire.[1] Typically square or polygonal in plan, with heights reaching 82 to 100 feet, they featured thick walls, multiple floors for living quarters and storage, and strategic placements within concentric defensive circuits including walls, ditches, and gatehouses.[1][2] Historical DevelopmentFortified towers peaked in construction during the 12th century, coinciding with the Norman Conquest and the spread of feudalism across Europe, where they served as administrative centers, symbols of power, and focal points for surrounding settlements.[2] By the late 12th century, advancements in siege technology—such as trebuchets and mining—prompted refinements like rounded corners on towers to deflect projectiles, as seen in examples like Clifford's Tower in York, rebuilt between 1245 and 1272 in a quatrefoil shape for enhanced defense.[1][2] Their role extended beyond pure military function; vassals gathered in the keep to pay homage to lords, underscoring the social hierarchy of medieval society.[1] Construction often involved local stone, with royal or noble patronage funding massive builds, such as the original 1086 timber keep of York Castle under William the Conqueror to subdue northern England.[2] Architectural Features and Purpose
The design emphasized resilience and self-sufficiency: ground floors housed armories or prisons, upper levels provided living spaces with fireplaces and latrines, and battlements allowed archers to defend the structure.[2] In tower keep castles, the keep stood as the principal element, often free-standing or integrated into an enclosure, with additional towers projecting from curtain walls for flanking fire.[2] Notable examples include the Arques keep in Aude, southern France (early 14th century, 82 feet tall) and Scarborough Castle's keep in England (mid-12th century, 100 feet), which illustrate the shift toward taller, more imposing forms to dominate landscapes and deter attackers.[1] While primarily defensive, these towers also reflected cultural prestige, evolving into more residential forms by the 14th and 15th centuries as the introduction of gunpowder artillery in the late 14th century began to undermine their defensive role, leading to obsolescence by the 16th century.[2][1]