In 1312 April 26, Henricus de Bello Monte (Henry Beaumont) was granted, by Edward II, (In year 5 of his reign) a Royal licence to crenellate Folkyngham (Folkingham Castle)

"Licence for Henry de Bello Monte to crenellate his dwelling-house (mansum suum) at Folkyngham, co. Lincoln."

Granted at Newcastle-upon-Tyne, by King.

Original source is

• Calendar of Patent Rolls (1307-13) p457

(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 p266n11
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p406

More details about licences to crenellate can be found here.

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