Lordship in the Welsh Marches, now in southeastern Wales. The town of Caerleon stands on the River Usk, some miles above Newport, and was once a Roman fort (its name means fortress of the legion).
The Lordship was established in southern Gwent by the end of the Conqueror’s reign in 1087. Early in the 12th century it came into the hands of the great family of Clare and was held by the Pembroke branch until 1176 and then by their heirs, the Marshal family, until their extinction in 1245.
The other great branch of the House of Clare, the Earls of Gloucester, then held it until their own extinction in 1314. The last Earl’s sister then held Caerleon until 1360, at first with her husband, Roger Amory, except for a few years after his execution in 1322, when it was swallowed into the burgeoning empire of the Despencers, an empire that crashed in 1326.
Lionel, Duke of Clarence, son of Edward III, held it from 1360 until his death in 1368, when it passed to his heiress and her husband’s family, the Mortimers. From them Caerleon passed to the Dukes of York in 1425 and thus to the Crown in 1461.
It formed part of southern Monmouthshire in 1536.