Raglan Castle (Welsh: Castell Rhaglan) is a significant late medieval castle located just north of the village of Raglan in the county of Monmouthshire in south east Wales. Its origins lie in the 12th century but the ruins visible today date from the 15th century and later. It is likely that the early castle followed the motte-and-bailey design of most castles of this period and location and some traces of this early history can still be seen. The peak of the power and splendour of the castle was attained in the 15th century and 16th century, as the Marches fortress of the great family of Herbert. Its ruination came at the end of one of the longest sieges of the English Civil War.