In 1264 March 16, Rogerus de Sumery was granted, by Henry III, (In year 48 of his reign) a Royal licence to crenellate Duddeleg (Dudley Castle)

"Licence for Roger de Sumery and his heirs to enclose the dwelling-place of his manor (mansum manerii sui) of Duddeleg, co. Stafford, and of Welegh, co. Worcester, with a ditch and a wall of stone and lime, and to fortify and crenellate it."

Granted at Oxford,

Original source is

• Calendar of Patent Rolls (1258-66) p307

(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., 1994, 'Freedom to Crenellate by Licence - An Historiographical Revision' Nottingham Medieval Studies Vol38 p130
  King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol2 p454n11
  Willis-Bund, J.W. (ed), 1913, 'Parishes: Dudley' VCH Worcester Vol3 p90-
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p402

More details about licences to crenellate can be found here.

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