Key Features and Defensive Layout of Kenilworth Castle

The Transition to Stone: The Great Tower

• A timber fortress is quick to build, but it is highly vulnerable to fire and rot.
• To create a permanent stronghold, construction of a stone Great Tower began around 1124 using locally quarried red sandstone.
• This central building is a hall keep. Unlike later tall, narrow towers, it was designed to be wider than it was high to accommodate both military and administrative functions.
• The structure was massive, originally standing 24 metres high with dimensions of approximately 24m by 19m.
• It featured exceptionally thick walls, measuring between 4.3 and 6 metres thick, which were designed specifically to withstand bombardment from siege engines.

Key Architectural Features of the Great Tower

• The structure was not a simple square block; it featured four massive square corner turrets that acted as pilaster buttresses to provide immense structural stability.
• The south-east turret held a crucial defensive feature: a deep well to ensure the garrison had a safe water supply during a siege.
• Access to the building was highly restricted by a forebuilding. This was a stone defensive structure containing a portcullis that protected the main entrance, which was deliberately placed on the first floor to prevent ground-level breaches.
• Internally, the ground floor consisted of an undercroft used for storing food and weapons, rather than for noble accommodation. The first floor contained the Great Hall, which served as the main room for lordship, administration, and justice.

Defensive Curtain Walls and Stone Towers

• Even the strongest central tower needs an outer layer of defence to keep attackers at a distance.
• During the late 12th century, King Henry II replaced the original timber palisade with a stone curtain wall to enclose the inner courtyard.
• In the early 13th century, King John expanded the fortress massively, spending over £1,100 to build a colossal outer circuit of stone walls. This enclosed an outer bailey that did not contain the main royal residence, but rather housed stables, kitchens, and service staff.
• King John also constructed heavily fortified outer towers, including Mortimer’s Tower, which served as a twin-towered gatehouse with a portcullis.
• Another key addition was Lunn’s Tower, a circular stone tower on the north-east corner. Its round shape eliminated weak corners to prevent enemy miners from collapsing it, and it featured unique fish-tailed arrow loops that gave archers a wider field of fire.

Water Defences and Earthworks

• Imagine trying to dig a tunnel under a castle wall, only to find you are separated by a massive 100-acre lake.
• King John significantly enlarged an existing small lake to create The Mere, a colossal artificial body of water measuring 800 metres long and 150 metres wide.
• This vast lake surrounded the west and south sides of the castle, making the fortress virtually impregnable to battering rams, siege towers, and enemy tunneling.
• To protect the main entrance and the dam that held back The Mere, an immense crescent-shaped earthwork known as The Brays was constructed later in the 13th century.
• The effectiveness of these water defences was proven during the great Siege of 1266, which lasted six months because the rebel garrison was so well protected by The Mere.

The Destruction of the Fortress

• A castle designed to withstand medieval catapults stood no chance against 17th-century politics.
• Following the English Civil War, Parliamentarian forces ordered the slighting of Kenilworth Castle in 1649 to ensure it could never again be used as a Royalist military stronghold.
• The north wall of the Great Tower and a northern section of the outer curtain wall were deliberately demolished with explosives.
• Finally, the great dam was breached to drain The Mere, permanently removing the water defences and turning the vast lake back into ordinary farmland.