Caerphilly Castle is a medieval fortification constructed by Gilbert de Clare in the 13th century. Surrounded by extensive artificial lakes – considered by historian Allen Brown to be 'the most elaborate water defences in all Britain' – it occupies around 30 acres and is the largest castle in Wales and the second-largest castle in the United Kingdom after Windsor Castle. It is famous for having introduced concentric castle defences to Britain and for its large gatehouses.
Gilbert began work on the castle in 1268 following his occupation of the north of Glamorgan, with the majority of the construction occurring over the next three years at a considerable cost. The project was opposed by Gilbert's Welsh rival Llywelyn ap Gruffudd, leading to the site being burnt in 1270 and taken over by royal officials in 1271. Despite these interruptions, Gilbert successfully completed the castle and took control of the region. The core of Caerphilly Castle, including the castle's luxurious accommodation, was built on what became a central island, surrounding by several artificial lakes, a design Gilbert probably derived from that at Kenilworth. The dams for these lakes were further fortified, and an island to the west provided additional protection. The concentric rings of walls inspired Edward I's castles.
The castle was attacked during the Madog ap Llywelyn revolt of 1294, the Llywelyn Bren uprising in 1316 and during the overthrow of Edward II in 1326–27. In the late 15th century, however, it fell into decline and by the 16th century the lakes had drained away and the walls were robbed of their stone. The Marquesses of Bute acquired the property in 1776 and under the third and fourth Marquesses extensive restoration took place. In 1950 the castle and grounds were given to the state and the water defences were re-flooded. In the 21st century, the Welsh heritage agency Cadw manages the site as a tourist attraction.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.