The Gatehouse website record of a licence to crenellate for Kingston upon Hull Town Wall granted on 1321 July 27

Licence for the burgesses and commonalty of Kyngeston on Hull to strengthen their town with ditches and a wall of stone and lime and to crenellate the wall. By K. on the information of Master R. de Baldok. (CPR)

Edward, by the grace of God King of England, Lord of Ireland, and Duke of Aquitaine, To all his Bailiffs and faithful subjects to whom the present letters shall come, Greeting. Know ye that of our special grace, and for the greater safety and security of our town of Kyngeston upon Hull, we have granted and given license, for us and heirs, to our beloved the Burgesses and Commonalty of the said town, that they may enclose the same town with moats and with a wall of stone and lime, and may crenellate that wall, and may hold the same town so enclosed, and the said wall so crenellated, to themselves their heirs and successors, Burgesses of the town aforesaid, for ever, without hindrance or impediment of us or our heirs, sheriffs, or other our bailiffs or ministers whomsoever: And therefore we do command you that ye shall not molest in any manner or burden the aforesaid Burgesses or Commonalty, or their heirs or successors, contrary to the tenor of the grant and licence aforesaid. In testimony whereof we have caused these our letters to be made patent. Witness ourself at Westminster, on the twenty-seventh day of July, in the fifteenth year of our reign.
By the present King himself,
to Master Robert de Baldok. (Boyle)

Original source is;

Lyte, H.C. Maxwell (ed), 1904, Calendar of Patent Rolls (1321-24) p. 7 online copy
Boyle, J. R., 1905, Charters and Letters Patent granted to Kingston upon Hull (Hull Corporation) p. 9
Boyle worte the original was preserved in the Hull City Corporation records. I am informed that as of 2010 that Hull City does not have the original and that Boyle was using a certified copy from the patent roll.

(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. Licentia is best translated as 'freedom to' not 'permission'.)

Significant later sources 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) p162
Coulson, C., 1994, 'Freedom to Crenellate by Licence - An Historiographical Revision' Nottingham Medieval Studies Vol. 38 p. 122
Turner, H.L., 1971, Town Defences in England and Wales (London) p. 103 (mistakenly as murage grant)

Baldock was keeper of the privy seal.

Biographical source include;

Roy Martin Haines, 2004, ‘Baldock, Robert (d. 1327)’ Oxford Dictionary of National Biography (Oxford University Press) online copy (subscription may be needed)

More information about licences to crenellate can be found here.

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