Nunney was considered a conservative, even slightly backward design and probably built to protect against French invasion. Historians such as Robert Liddiard and Matthew Johnson are now less certain. Nunney is regarded as a bold, striking design, similar in many ways to those at Herstmonceux or Saltwood Castle. Whilst Nunney does resemble many French castles, there is no direct evidence that it was built in imitation of these designs, and indeed there are other English castles, such as Mulgrave and Dudley, that have a similar structure to Nunney's. Nunney Castle may be better understood instead as characteristic of a wider range of tower-keeps built in England during the period, designed, as Nigel Pounds puts it, "to allow very rich men to live in luxury and splendour."