Cardiff Castle (Welsh: Castell Caerdydd) is a medieval castle and Victorian architecture Gothic revival mansion, transformed from a Norman keep erected over a Roman fort in the Castle Quarter of Cardiff, the capital of Wales. There may have been at least two previous Roman forts on the site. The first was probably built about AD 55 during the conquest of the Silures tribe. From the late 2nd to the mid-3rd century, civilian buildings associated with iron working occupied the site The Norman keep was built on a high motte on the site of a Roman castra, first uncovered during the third Marquess of Bute's building campaign. The Norman keep, of which the shell remains, was constructed about 1091 by Robert Fitzhamon, lord of Gloucester and conqueror of Glamorgan. After the failed attempt of Robert Curthose, duke of Normandy, William the Conqueror's eldest son, to take England from Henry I, Robert of Normandy was imprisoned here until his death in 1134.[he castle, rebuilt in stone, was an important stronghold of Marcher Lords, in the de Clare and le Despenser dynasties, also the Beauchamps Earls of Warwick, Richard of York through his marriage into the Neville family, and the Herbert family, Earls of Pembroke. In the 18th century the castle became the property of John Stuart, 3rd Earl of Bute, who became through his Herbert wife a major landowner in the area, and whose heirs developed the docks that transformed Cardiff from a fishing village to a major coal exporting port during the 19th century.