Caerphilly Castle Caerphilly Castle ( ) is a medieval fortification in Caerphilly in South Wales . The castle was constructed by Gilbert de Clare in the 13th century as part of his campaign to conquer Glamorgan , and saw extensive fighting between Gilbert and his descendants and the native Welsh rulers . Surrounded by extensive artificial lakes – considered by historian Allen Brown to be " the most elaborate water defences in all Britain " – it occupies around and is the second largest castle in Britain . It is famous for having introduced concentric castle defences to Britain and for its large gatehouse s . 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 in North Wales , and proved what historian Norman Pounds has termed " a turning point in the history of the castle in Britain " . 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 . History . 13th century . Caerphilly Castle was built in the second half of the 13th century , as part of the Anglo - Norman expansion into South Wales . The Normans began to make incursions into Wales from the late 1060s onwards , pushing westwards from their bases in recently occupied England . Their advance was marked by the construction of castles and the creation of regional lordships . The task of subduing the region of Glamorgan was given to the earls of Gloucester in 1093 ; efforts continued throughout the 12th and early 13th centuries , accompanied by extensive fighting between the Anglo - Norman lords and local Welsh rulers . The powerful de Clare family acquired the earldom in 1217 and continued to attempt to conquer the whole of the Glamorgan region . In 1263 , Gilbert de Clare , also known as " Red Gilbert " because of the colour of his hair , inherited the family lands . Opposing him in Glamorgan was the native Welsh prince Llywelyn the Last . Llweyln had taken advantage of the chaos of the civil war in England between Henry III and rebel barons during the 1260s to expand his power across the region . In 1265 Llywelyn allied himself with the baronial faction in England in exchange for being granted authority over the local Welsh magnates across all the territories in the region , including Glamorgan . De Clare believed his lands and power were under threat and allied himself with Henry III against the rebel barons and Llywelyn . The baronial revolt was crushed between 1266 and 1267 , leaving de Clare free to advance north into Glamorgan from his main base in Cardiff . De Clare started to construct a castle at Caerphilly to control his new gains in 1268 . The castle lay in a basin of the Rhymney Valley , alongside the Rhymney River and at the heart of network of paths and roads , adjacent to a former Roman fort . Work began at a huge pace , with ditches cut to form the basic shape of the castle , temporary wooden palisade s erected and extensive water defences created by damning a local stream . The walls and internal buildings were built at speed , forming the main part of the castle . The architect of the castle and the precise cost of the construction are unknown , but modern estimates suggest that it could have cost as much as castles such as Conwy or Caernarfon , perhaps as much as £19 , 000 , a huge sum for the period . Llywelyn responded by intervening with his own forces but outright conflict was prevented by the diplomatic efforts of Henry III . De Clare continued building work and in 1270 Llywelyn responded by attacking and burning the site , probably destroying the temporary defences and stores . De Clare began work again the following year , raising tensions and prompting Henry to send two bishops , Roger de Meyland and Godfrey Giffard , to take control of the site and arbitrate a solution to the dispute . The bishops took possession of the castle later in 1271 and promised Llywelyn that building work would temporarily cease and that negotiations would begin the following summer . In February of the next year , however , de Clare ' s men seized back the castle , threw out the bishops ' soldiers , and de Clare – protesting his innocence in these events – began work once again . Neither Henry nor Llywelyn could readily intervene and de Clare was able to lay claim to the whole of Glamorgan . Work on the castle continued , with additional water defences , towers and gatehouse s added . Llywelyn ' s power declined over the next two decades . In 1276 Henry ' s son , Edward I , invaded Wales following a dispute with the prince , breaking his power in South Wales , and in 1282 Edward ' s second campaign resulted in Llwelyn ' s death and the collapse of independent Welsh rule . Further defences were added to the walls until work stopped around 1290 . Local disputes remained . De Clare argued with Humphrey de Bohun , the earl of Hereford , in 1290 and the following year the case was brought before the king , resulting in the temporary royal seizure of Caerphilly . In 1294 Madog ap Llywelyn rebelled against English rule , the first major insurrection since the 1282 campaign . The Welsh appear to have risen up over the introduction of taxation and Madog had considerable popular support . In Glamorgan , Morgan ap Maredudd led the local uprising ; Morgan had been dispossessed by de Clare in 1270 and saw this as a chance to regain his lands . Morgan attacked Caerphilly , burning half of the town , but failed to take the castle . In the spring of 1295 Edward pressed home a counter - attack in North Wales , putting down the uprising and killing Madog . De Clare attacked Morgan ' s forces and retook the region between April and May , resulting in Morgan ' s surrender . De Clare died at the end of 1295 , leaving Caerphilly Castle in a good condition , linked to the small town of Caerphilly which had emerged to the south of it and a large deer park in the nearby Aber Valley . 14th – 17th centuries . Gilbert ' s son , also called Gilbert de Clare , inherited the castle , but he died fighting at the battle of Bannockburn in 1314 while still quite young . The family ' s lands were initially placed under the control of the Crown , but before any decision could be taken on the inheritance , a revolt broke out in Glamorgan . Anger over the actions of the royal administrators caused Llywelyn Bren to rise up in January 1316 , attacking Caerphilly Castle with a large force of men . The castle withstood the attack , but the town was destroyed and the rebellion spread . A royal army was despatched to deal with the situation , defeating Bren in a battle at Caerphilly Mountain and breaking the Welsh siege of the castle . In 1317 Edward II settled the inheritance of Glamorgan and Caerphilly Castle on Eleanor de Clare , who had married the royal favourite , Hugh le Despenser . Hugh used his relationship with the king to expand his power across the region , taking over lands throughout South Wales . Hugh employed Master Thomas de la Bataile and William Hurley to expand the Great Hall at the castle , including richly carved windows and doors . In 1326 , however , Edward ' s wife , Isabella of France , overthrew his government , forcing the king and Hugh to flee west . The pair stayed in Caerphilly Castle at the end of October and early November , before leaving to escape Isabella ' s approaching forces , abandoning the extensive stores and £14 , 000 held at the castle . William la Zouche besieged the castle with a force of 425 soldiers , cornering the constable , Sir John de Felton , Hugh ' s son – also called Hugh – and the garrison of 130 men inside . Caerphilly held out until March 1327 , when the garrison surrendered on the condition that the younger Hugh was pardoned , his father having been already executed . Tensions between the Welsh and the English persisted and spilled over in 1400 with the outbreak of the Glyndŵr Rising . It is uncertain what part the castle played in the conflict , but it seems to have survived intact . In 1416 , the castle passed through Isabel le Despenser in marriage to her first husband Richard de Beaumchamp , the earl of Worcester , and then to her second husband , Richard Beauchamp , the earl of Warwick . Isabel and her second husband invested heavily in the castle , conducting repairs and making it suitable for use as their main residence in the region . The castle passed to Richard Neville in 1449 and to Jasper Tudor , the earl of Pembroke , in 1486 . After 1486 , the castle went into decline , eclipsed by the more fashionable residence of Cardiff Castle ; once the sluice - gates fell into disrepair , the water defences probably drained away . Antiquarian John Leland visited Caerphilly Castle around 1539 , and described it as having " waulles of a wonderful thiknes " , but beyond a tower used to hold prisoners it was in ruins and surrounded by marshland . Henry Herbert , the earl of Pembroke used the castle for his manorial court . In 1583 the castle was leased to Thomas Lewis , who stripped it of much of its stone to extend his house , causing extensive damage . In 1642 the English Civil War broke out between the Royalist supporters of Charles I and those of Parliament . South Wales was predominantly Royalist in sympathy , and during the conflict , a sconce , or small fort , was built overlooking Caerphilly Castle to the north - west , on the site of the old Roman fort . It is uncertain if this was built by Royalist forces or by the Parliamentary army that occupied the area during the final months of the war in March 1646 , but the fort ' s guns would have dominated the interior of the castle . It is also uncertain whether or not Caerphilly Castle was deliberately slighted by Parliament to prevent its future use as a fortification . Although several towers had collapsed by the 18th century , possibly as a result of such an operation , it is probable that this deterioration was actually the result of subsidence damage caused when the water defences retreated , as there is no evidence of deliberate destruction having been ordered . 18th – 21st centuries . The Marquesses of Bute acquired the castle in 1776 . John Stuart , the first marquess , took steps to protect the ruins . His great - grandson John , the third marquess , was immensely rich as the result of the family ' s holdings in the South Wales coalfields and was passionately interested in the medieval period . He had the site fully surveyed by the architect William Frame , and reroofed the great hall in the 1870s . The marquess began a process of buying back leasehold properties around the castle with the intent of clearing back the town houses that had been built up to the edge of the site . The fourth marquess , John was an enthusiastic restorer and builder and commissioned a major restoration project between 1928 and 1939 . The stonework was carefully repaired , with moulds made to recreate missing pieces . The Inner East Gatehouse was rebuilt , along with several of the other towers . The marquess carried out landscaping work , with the intent of eventually re - flooding the lakes , and thanks to several decades of purchases was finally able to demolish the local houses encroaching on the view of the castle . By 1947 , when John Crichton - Stuart , the fifth marquess , inherited the castle , the Bute family had divested itself of most of its land in South Wales . John sold off the family ' s remaining property interests and in 1950 he gave Caerphilly Castle to the state . The lakes were re - flooded and the final stages of the restoration work were completed in the 1950s and 1960s . In the 21st century the castle is managed by the Welsh heritage agency Cadw as a tourist attraction . In 2006 , the castle saw 90 , 914 visitors . It is protected as a scheduled monument and as a grade I listed building . Architecture . Caerphilly Castle comprises a set of eastern defences , protected by the Outer East Moat and the North Lake , and fortifications on the Central Island and the Western Island , both protected by the South Lake . The site is around in size , making it the second largest in Britain . It is constructed on a natural gravel bank in the local river basin , and the castle walls are built from Pennant sandstone . The castle ' s architecture is famous and historically significant . The castle introduced concentric castle defences to Britain , changing the future course of the country ' s military architecture , and also incorporated a huge gatehouse . The castle also featured a sophisticated network of moats and dams , considered by historian Allen Brown to be " the most elaborate water defences in all Britain " . The eastern defences were reached via the Outer Main Gatehouse , which featured circular towers resting on spurred , pyramidic bases , a design particular to South Wales castles . Originally the gatehouse would have been reached over a sequence of two drawbridges , linked by an intervening tower , since destroyed . To the north side of the gatehouse was the North Dam , protected by three substantial towers , and which may have supported the castle ' s stables . Despite subsidence damage , the dam still holds back the North Lake . The South Dam was a massive structure , long , ending in a huge buttressed wall . The remains of the castle mill – originally powered by water from the dam – survive . Four replica siege engine s have been placed on display . The dam ended in Felton ' s Tower , a square fortification designed to protect the sluicegates regulating the water levels of the dam , and the South Gatehouse – also called Giffard ' s Tower – originally accessed via a drawbridge , which led into the town . Caerphilly ' s water defences were almost certainly inspired by those at Kenilworth , where a similar set of artificial lakes and dams was created . Gilbert de Clare had fought at the siege of Kenilworth in 1266 and would have seen these at first hand . Caerphilly ' s water defences provided particular protection against mining , which could otherwise undermine castle walls during the period , and are considered the most advanced of their kind in Britain . The central island held Caerphilly ' s inner defences , a roughly square design with a walled inner and middle ward , the inner ward protected by four turrets on each of the corners . The walls of the inner ward overlooked those of the middle ward , producing a concentric defence of two enclosed rings of walls ; in the medieval period , the walls of the middle ward would have been much higher than today , forming a more substantial defence . Caerphilly was the first concentric castle in England , pre - dating Edward I ' s famous programme of concentric castles by a few years . The design influenced the design of Edward ' s later castles in North Wales , and historian Norman Pounds considers it " a turning point in the history of the castle in Britain " . Probable subsidence has caused the south - east tower in the Inner Ward to lean outwards at an angle of 10 degrees . Access to the central island occurred over a drawbridge , through a pair of gatehouses on the eastern side . Caerphilly Castle ' s Inner East Gatehouse , based on the gatehouse built at Tonbridge in the 1250s , reinforced a trend in gatehouse design across England and Wales . Sometimes termed a keep - gatehouse , the fortification had both exterior and interior defences , enabling it to be defended even if the perimeter of the castle was breached . Two huge towers flanked the gatehouse on either side of an entrance that was protected by portcullis es and murder - hole s . The substantial size of the gatehouse allowed it to be used for accommodation as well as defence and it was comfortably equipped on a grand scale , probably for the use of the castle constable and his family . Another pair of gatehouses protected the west side . Inside the inner ward was the castle ' s Great Hall and accommodation . Caerphilly was built with fashionable , high - status accommodation , similar to that built around the same time in Chepstow Castle . In the medieval period the Great Hall would have been subdivided with wooden screens , colourful decorations , with rich , detailed carving and warmed by a large , central fireplace . Some carved medieval corbel s in the shape of male and female heads survive in the hall today , possibly depicting the royal court in the 1320s , including Edward II , Isabella of France , Hugh Despenser and Eleanor de Clare . To the east of the Great Hall was the castle chapel , positioned above the buttery and pantry . On the west side of the hall were the castle ' s private apartments , two solar blocks with luxurious fittings . Beyond the central island was the Western Island , probably reached by drawbridges . The island is called " Y Weringaer " or " Caer y Werin " in Welsh , meaning " the people ' s fort " , and may have been used by the town of Caerphilly for protection during conflicts . On the north - west side of the Western Island was the site of the former Roman fort , enclosing around , and the remains of the 17th - century civil - war fortification built on the same location .