In 1317 Sept 25, Galfridus Le Scrop (Geoffrey le Scrope) was granted, by Edward II, (In year 11 of his reign) a Royal licence to crenellate Clifton super Yoram (Clifton Castle)

"Licence for Geoffrey Lescrope to crenellate his dwelling place (mansum) of Clifton-upon-Yore, co. York."

Granted at York, by King.

Original source is

• Calendar of Patent Rolls (1317-21) p26

(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, 1996, Greater Medieval Houses Vol1 (Cambridge) p421
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p407

More details about licences to crenellate can be found here.

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