In 1298 Aug 21, Johannes de Cadamo (M. John of Caen) was granted, by Edward I, (In year 26 of his reign) a Royal licence to crenellate domos suas quas habet infra clausum Ebor. ecclesi (John of Caen House, York Cathedral Close)

"domos suas quas habet infra clausum Ebor. ecclesi"

Granted at Linton Roderick, by privy seal.

Original source is

• Calendar of Patent Rolls (1292-1301) p358

(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., 1995, 'Battlements and the Bourgeoisie: Municipal Status and the Apparatus of Urban Defence' in Church, Stephen (ed), Medieval Knighthood Vol. 5 (Boydell) p165n189
  Coulson, C., 1982, 'Hierarchism in Conventual Crenellation' Medieval Archaeology Vol26 p93
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p404

More details about licences to crenellate can be found here.

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