In 1347 Jan 6, Ricardus de Merton (Richard de Merton) was granted, by Edward III, (In year 20 of his reign) a Confirmation licence to crenellate Torriton (Torrington Castle, Great Torrington)

"Licence, in consideration of his good service in the war with France (pro bono servitio quod nobis in guerra nostra Franc. impendit), for Richard de Morton to crenellate his dwelling-place (mansum) of Torriton, co. Devon."

Granted at Reading, by privy seal.

Built in the reign of John by William de Toriton and was ordered to be destroyed in 1228 having been built without a Licence. it was rebuilt in 1340 by Richard de Merton, who obtained licences to crenellate in 1328 (an application), 1340 (the grant) and 1347 (a repeat).

Original source is

• Calendar of Patent Rolls (1345-48) p228

(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, 2006, Greater Medieval Houses Vol3 (Cambridge) p695
  Higham, R. A., 1988, 'Devon Castles: an annotated list' Proceedings of the Devon Archaeological Society Vol46 p146
  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.

Please let me know if you see any errors, can add information or can otherwise help to improve this resource. Contact me