Including its moats and outlying areas, the 30 acre castle at Caerphilly is the largest in Wales, and second in size only to Windsor in the whole of Britain. The fortification was constructed towards the end of the 13th century by English nobleman Gilbert de Clare (known as Gilbert the Red on account of the fiery colour of his hair), and was in active use for about 200 years before becoming disused and eventually partly ruined, however later renovations in several phases, mostly in the 19th and 20th centuries, resulted in the majority of the structure being completely restored, both the buildings and their extensive water defences. It is now amongst the most visited of the historic sites managed by Cadw, and dominates the centre of Caerphilly. The castle is also notable for its three stage concentric design - walls within walls within walls, the earliest of this type in the country.
The main castle entrance is on the east side, protected by a deep moat and two lengthy wall sections, built on banks that also act as dams for two lakes on the far side. The outermost gatehouse is entered via a bridge over the moat, and gives access to the outer ward, which is linked to the inner section of the castle by a second bridge. All this is surrounded by water, and contains, within another set of walls, the main buildings, which include the great hall, apartments, and four large, turreted corner towers. A rear entrance bridges the inner moat to an intermediate defensive area, known as the horn work.
The enclosed parts of the site are not so numerous, but the whole place is extensive, and at least two hours is needed to explore all areas; more if walking all around the perimeter of the lakes. The best views are of the central section from the outside, and from the top of the towers, looking out across the walls and the lakes; the inner ward is somewhat less photogenic, partly due to a proliferation of modern facilities, sometimes placed in unsympathetic places - waste bins, signs, benches, fences, fire notices, etc, which detract somewhat from the authenticity.
Castle visitors are able to use a large, free carpark just five minute's walk away, beside Morrison's supermarket. On the far side of nearby Castle Street, the land rises a little to form a low, grassy embankment, with a path along the top, and the outer east moat on the far side. The moat is relatively narrow to the north, where the far side borders another bank, below a wall reinforced with three towers and the north gatehouse, but wider to the south, as here the waters extend right up to the buttressed south wall. Both these wall sections are built on earthworks which act as dams for the two lakes beyond; for the southern section, the walls continue around a curved buttress and along the far side, adjoining the south lake, and enclosing the outer ward. Access to the castle is via a bridge over a narrow section of the moat, then through the outer main gatehouse, to a fenced viewing area, from where visitors proceed through the Cadw information building, where fees are paid to access the castle interior.
The outer gatehouse is complete, but not generally open to the public. The closest section of the castle is the outer ward, also the south dam platform; this extends 500 feet south, ending with a curved wall section containing the south gatehouse, usually closed, and the remains of Felton's tower on the east side, overlooking the end of the outer moat. Most of this enclosure is empty, apart from four reproduction wooden siege engines, and the low remains of the castle mill, once operated using water from the dam.
The central section of the castle is entered via a bridge over the inner moat, an extension of the south lake, leading to the outer east gatehouse, set between two towers which are complete at the front but missing their rear sections. Beyond is the middle ward, a grassy enclosure with low walls all around the outside, adjoining the moat, and on the inside bordering the much higher walls of the inner ward. A path goes most of the way round the middle ward, just not to the south, as here ruins of the kitchen and south tower occupy all of the area between the moat and the inner wall. The final structure guarding the inner ward is the inner east gatehouse, the strongest of all the entrances, flanked by two especially sturdy towers that contain several differently-sized rooms, on three levels, some once used for accommodation. Both sides of the gatehouse are accessed via stairways, which continue to viewing areas on the roofs. The first floor rooms link with passageways along the top of the curtain walls in both directions; the north path runs past the incomplete northeast tower and along a partly roofed corridor to the northwest tower (which also contains a staircase to the top), while to the south the other walkway moves briefly outside, then connects with an enclosed passageway linking to another stairway, from the vicinity of the hall. The walkway passes the southeast tower which is notable for its angled appearance, standing at about ten degrees away from vertical, due to subsidence.
Within the square-shaped inner ward are several buildings, all on the south side; ruins of the chapel, pantry, buttery and a two floor apartment, and the restored great hall, complete with metal roof installed the 1870s. The hall is partly furnished, in an authentic style, and is used on occasions to stage weddings and other events. On the far side of the inner ward is the inner west gatehouse, between two more towers, and this opens out back to the middle ward where yet another set of doors, in the outer west gatehouse, link with a bridge over the moat and to the intermediate walled area (horn work), that was probably used by residents of the local town during times of attack. One more bridge connects this to the surrounding land, beyond the outer moat.
Gilbert de Clare, 7th Earl of Gloucester and 3rd Lord of Glamorgan (died 1295), was a leading figure in the English expansion into south Wales during the 13th century, in conjunction with Henry III; the castle at Caerphilly was built in order to consolidate advances made in 1267, following defeat of a rebel Welsh faction led by Llewellyn ap Gruffudd, and so is somewhat more recent than most other castles hereabouts. Right from the start its defences were formidable, using a local stream to create the various moats and lakes, a design probably inspired by the similar fortifications at Kenilworth Castle, previously visited by de Clare. The structure, which used local Pennant sandstone, grey in colour, was largely complete by about 1290 (the only significant later modifications were the great hall and adjacent buildings, around 1325), and was involved in various raids and sieges over the next few decades, during and after which time it changed ownership on several occasions, until acquired by the Earls of Pembroke in 1486, by which stage it was no longer required for military purposes. The place soon declined, in part due to removal of masonry for other projects, and partly due to subsidences caused by drying up of the surrounding lakes. Restoration was undertaken following acquisition by the Marquesses of Bute at the end of the 18th century, and continued at intervals until the mid 20th century, culminating in the re-creation of the lakes.