In 1340 May 11, Thomas de Blenkensop (Thomas de Blencansopp) was granted, by Edward III, (In year 14 of his reign) a Confirmation licence to crenellate Blenkensop (Blenkinsopp Castle)

"mansum suum de Blenkensope"

Granted at Westminster, by privy seal.

Repeat or ratification of licence issued in King's name in February.

Original source is

• Calendar of Patent Rolls (1338-40) p524

(In fact, the original source given is usually a transcription/translation of what are precious medieval documents not readily availably. It should be noted that these transcription/translations often date to the nineteenth or early twentieth centuries and that unwitting bias of transcribers may affect the translation. Care should also be taken to avoid giving modern meaning to the medieval use of certain stock words and terms.)

Significant later source are;

• Emery, Anthony, 1996, Greater Medieval Houses Vol1 (Cambridge) p159
  Bates, C.J., 1891, Border Holds of Northumberland (London and Newcastle: Andrew Reid) p9
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p412

More details about licences to crenellate can be found here.

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