In 1470, Christopher Conyers, knight was granted, by Bishop Lawrence Booth, (In year 13 of his reign) a Durham licence to crenellate Sokburn (Sockburn Castle)

"Has licence to enclose with a wall and fortify his manor of Sokburn."

Original source is

• 1873, Report of the Deputy Keeper Public Records Vol35 p97

(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) p160
  King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p141n29
  Page, Wm (ed), 1914, VCH York, North Riding Vol1 p449n4
  Hutchinson, Wm, 1785-94, The History and Antiquities of the County Palatine of Durham Vol2 p149
  Hutchinson, Wm, 1785-94, The History and Antiquities of the County Palatine of Durham Vol1 p359

More details about licences to crenellate can be found here.

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