In 1271 Jan 17, Stephanus de Penecestr was granted, by Henry III, (In year 55 of his reign) a Royal licence to crenellate Hevre (Hever Castle)

"Licence for Stephen de Penecestre to strengthen his house (domum suam) of Hevre, co. Kent, with a wall of stone and lime and to crenellate it in the manner of a castle."

Granted at Westminster,

Licenses to crenallate dated 1271, 1340 and 1384.

Original source is

• Calendar of Patent Rolls (1266-72) p507

(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;

• King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p241n30
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p403

More details about licences to crenellate can be found here.

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