John of Monmouth (died 1257)

He was the son of John of Monmouth and his second wife Agnes, daughter of Walter de Muscegros.

[2] Penrhos Castle was the focus of a sharp dispute the younger John of Monmouth had with William III de Cantilupe.

[3] There are official records showing that John was appointed custos of the castle in 1251, and William was pardoned the following year for demolishing it.

[5] John of Monmouth died, according to the Victoria County History of Dorset, without issue.

[8] It is stated that John of Monmouth married a daughter of David, Earl of Huntingdon.