In Welsh Caerphilly castle is called Castell Caerffili.
Unlike many other great 13th-century Welsh castles, Caerphilly Castle was not built by Edward I in his suppression of the Welsh lords. It was built by Gilbert 'the Red' de Clare, a powerful, red-headed nobleman of Norman descent, during a dispute with the Prince of Gwynedd, Llywelyn the Last.
The dispute was mediated by King Henry III (1216-1272), who sent a bishop to take temporary control of the castle until matters could be settled. However, de Clare regained control of the castle and occupied it until his death in 1295.
The forces of Owain Glyndwr captured Caerphilly Castle in 1403, but the occupation lasted only one hundred days. The Welsh returned in 1405 with French forces at the height of the rebellion and retook the castle. They held it for a year, the garrison only leaving after setbacks elsewhere changed the dynamics of the revolt in south Wales.
Some maintenance was done by subsequent owners, Richard Beauchamp (d. 1439), Richard Neville (d. 1471) and Jasper Tudor (d. 1495), probably because of its strategic usefulness.
The castle gradually fell into disrepair from the fifteenth century, though some maintenance was done on parts of it, notably the eastern gate house which was used as a prison. Despite being largely untouched by the Civil War of 1642-1648, damage inflicted by Cromwell's Parliamentary Army in 1648 is said to have led to one of the most notable features of the castle, its leaning south-east tower. The tower stands 20 metres high and leans 3 metres from the perpendicular.
Disrepair continued until the late 18th century when the first Marquis of Bute began preservation work. Three generations of Marquises recorded the details of the castle, cleared structures built against its walls as leases ended and eventually undertook painstaking analysis and restoration of the fallen masonry. During the 1930s, surrounding streets were levelled to restore the view which had been obscured by town development.
In 1950, the then owner, the 5th Marquis of Bute presented Caerphilly Castle to the British government; its restoration and preservation is continued today by Cadw.
Interior of t he Great Hall