Gilbert de Clare built a stone castle on this site between 1267 and 1277. The 3rd Marquess of Bute commissioned William Burges to rebuild it as a summer residence. George Thomas Clark surveyed the ruins in 1850. Rebuilding began in 1875, the external work was largely complete by the end of 1879, and the interior was finished in 1891. After Burges died in 1881, Richard Pullan took over, and William Frame directed the interior work.
The style is High Victorian Gothic Revival. The exterior imitates 13th-century English design but uses conical roofs more typical of French or Swiss fortifications. Older sections are red sandstone and grey limestone, and the additions are red Pennant sandstone. The Banqueting Hall has a 35-foot (11 m) ceiling.
It was used rarely by the Bute family. It passed into state care in 1950, and Cadw has controlled it since 1984. It is a Grade I listed building.

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