In 1345 April 9, Gilbertus de Whitleye (Gilbert de Whitley) was granted, by Edward III, (In year 19 of his reign) a Royal licence to crenellate Whitleye (Whitley Tower)

"mansum suum de Whitleye"

Granted at Westminster, by privy seal.

Original source is

• Calendar of Patent Rolls (1343-45) p446

(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
  King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol2 p377n481
  Bates, C.J., 1891, Border Holds of Northumberland (London and Newcastle: Andrew Reid) p10
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p414

More details about licences to crenellate can be found here.

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