In 1397 Feb 12, Willielmus Stukeland [Stirkeland], clericus (William Strickland) was granted, by Richard II, (In year 20 of his reign) a Royal licence to crenellate Penreth (Penrith Castle)

"quandam cameram suam in villa de Penreth
Licence for William Stirkeland, clerk, to crenellate his chamber in Penreth in the March of Scotland"

Granted at Westminster, by King.

In 1397 William Strickland obtained a licence to strengthen and crenellate his pele tower. Two years later a further licence was granted to build a barmkin.

Original source is

• Calendar of Patent Rolls (1396-99) p66

(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;

• Thompson, M.W., 1998, Medieval bishops' houses in England and Wales (Aldershot: Ashgate Publishing) p168
  Emery, Anthony, 1996, Greater Medieval Houses Vol1 (Cambridge) p263
  King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p99n57
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p420

More details about licences to crenellate can be found here.

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