In 1373 March 5, Abbas et Conventus de Wynchecombe was granted, by Edward III, (In year 47 of his reign) a Royal licence to crenellate Wynchecombe (Winchcombe Abbey)

"Licence, at the request of the king's clerk, Master John de Branketre, for the abbot and convent of Wynchecombe to crenellate their abbey and the houses and buildings of the same. (Abbatiam suam ac domos et edificia ejusdem)"

Granted at Westminster, by King.

At the request of the king's clerk, Master John de Branketre.

Original source is

• Calendar of Patent Rolls (1370-74) p260
  Royce, Landboc sive Registrum Monasterii de Winchelcumba Vol2 p129

(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;

• Coulson, C., 1982, 'Hierarchism in Conventual Crenellation' Medieval Archaeology Vol26 p89, 94
  Page, Wm (ed), 1907, Citation: 'Houses of Benedictine monks: The abbey of Winchcombe' VCH Gloucester Vol2 p66-72
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p417

More details about licences to crenellate can be found here.

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