The Welsh Behemoth
Dominating the town of Caerphilly in South Wales, Caerphilly Castle (Castell Caerffili) is a fortress of superlatives. It is the largest castle in Wales and the second largest in Britain (after Windsor). Covering a massive 30 acres, it is a stone giant that changed the face of military architecture forever. Built with lightning speed in the late 13th century by the powerful Norman lord Gilbert de Clare, known as "The Red Earl," it was designed to crush the resistance of the Welsh prince Llywelyn ap Gruffudd. It introduced the "concentric" castle design to Britainâwalls within wallsâcreating a defensive machine that was virtually impregnable.
Walking across its wooden bridges and through its massive gatehouses is an awe-inspiring experience. The sheer scale of the water defenses and the height of the walls make you feel small. It is a place of raw power, where the ambition of a Norman baron met the defiance of the Welsh princes. It remains one of the greatest medieval castles in Western Europe.
History: A Race Against Time
The construction of Caerphilly was a high-stakes race. In 1268, Gilbert de Clare began building on a strategic marshland to block Llywelyn's advance into the south. Llywelyn realized the threat immediately and attacked, burning the initial works. Gilbert persisted, bringing in hundreds of masons and soldiers. By 1271, the main defenses were complete. It was a technological marvel of its age, the medieval equivalent of an aircraft carrier. Gilbert's ruthlessness and speed ensured the castle stood firm.
The castle saw action again during the rebellion of Madog ap Llywelyn in 1294 and the revolt of Llywelyn Bren in 1316. In the 14th century, it was transformed into a palatial home by the Despenser family, who added the Great Hall. However, its decline began in the 15th century. By the time of the English Civil War in the 1640s, it was already a ruin, though still strong enough to worry the Parliamentarian forces, who attempted to destroy it to prevent it from being used by Royalists.
Architecture: Walls of Water and Stone
Caerphilly is the first truly concentric castle in Britain. This means it has an inner ward surrounded completely by an outer ward. If attackers breached the first wall, they were trapped in the "killing zone" between the two, under fire from the higher inner wall. This design became the standard for Edward I's later castles in North Wales.
The Water Defenses
But the castle's greatest weapon was water. De Clare dammed the local streams to create huge artificial lakes (the Northern and Southern Lakes) and moats. These water barriers made it impossible for enemies to use siege towers or to mine (tunnel) under the walls. The massive Dam Platform on the eastern side is a wonder of medieval civil engineering, acting as both a dam and a fortified fighting platform.
The Leaning Tower
The most famous feature of Caerphilly is the South-East Tower. It leans at a perilous angle of 10 degreesâthat's significantly more than the Leaning Tower of Pisa! The cause of the lean is still debated. Some say it was subsidence due to the marshy ground. The more dramatic (and likely) story is that during the Civil War, Cromwell's troops tried to "slight" (destroy) the castle using gunpowder. The explosion shattered the tower's base, causing it to snap and tilt, but remarkably, it didn't fall. It has stood in this frozen fall for nearly 400 years, a testament to the strength of the mortar.
The Great Hall
The Great Hall has been magnificently restored. With its high wooden roof and large windows, it gives a sense of the castle's 14th-century splendor. It is often used for weddings and banquets, allowing modern visitors to feast like the Red Earl. The hall displays replicas of medieval siege engines, giving context to the castle's martial purpose.
Legends: The Green Lady
The castle is said to be haunted by the "Green Lady," the spirit of Alice de la Marche. Alice was the wife of Gilbert de Clare. Legend says she fell in love with a Welsh prince, Gruffudd the Fair. When Gilbert discovered the affair, he had Gruffudd executed. Alice died of a broken heart (or was perhaps murdered by her jealous husband). Her ghost, dressed in green robes, is said to wander the ramparts, waiting for her lost lover. Visitors have reported sudden drops in temperature and the feeling of being watched near the Dam Platform. Her tragic story adds a human dimension to the cold stone walls.
Visitor Information
Getting There
Caerphilly Castle is located in the center of Caerphilly town, about 8 miles north of Cardiff. It is easily accessible by train (Caerphilly station is a 10-minute walk) or by bus from Cardiff. There is a pay-and-display car park directly opposite the entrance. The castle dominates the town center.
Tours and Dragons
The castle is managed by Cadw (the Welsh historic monuments agency). It is open daily. There is a visitor center with a gift shop. Since 2017, the castle has been the lair of the "Caerphilly Dragons"âmassive animatronic dragons (Dewi, Dwynwen, and their babies) that live in the castle grounds. They smoke and roar, making the castle a huge hit with children. The castle also hosts regular re-enactment events, jousts, and the "Big Cheese" festival (celebrating Caerphilly cheese) in the summer.
Film Fame
Fans of BBC's Merlin and Doctor Who will recognize the castle immediately, as it has been a frequent filming location for both series, standing in for Camelot and various alien planets. Walking the corridors is like stepping onto a film set.