In 1267 Dec 5, Johannes Cumyn (John Comyn) was granted, by Henry III, (In year 52 of his reign) a Royal licence to crenellate Tyrsete (Tarset Castle)

"Pro Johanne Cumyn. De firmacione et kernellacione domus sue. Rex omnibus &c. salutem. Sciatis quod concessimus pro nobis et heredibus nostris dilecto et fideli nostro Johanni Cumyn quod quandam cameram infra manerium suum de Tyrsete in comitata Northumbr' construere proponit, fossato et muro de petra et calce includere, firmare et kernellare possit ad voluntatem ipsius Johannis, et cameram illam taliter fimatam et kernellatam tenere sibi et heredibus suis imperpetuum, sine occasione vel impedimento nostro vel heredum nostrorum. Ita tamen quod idem Johannes cameram illam eodem modo includat firmat et kernellet quo camera dilecti et fidelis nostri Ade de Gesemuth apud Heton in comitatu predicto est inclusa, firmata et kernellata, In cujus, &c. Teste Rege apud Westmonasterium v. die Dec."

Granted at Westminster, by King.

King writes "a very detailed licence for a Scotsman, John Cumyn, to enclose and crenellate a chamber (i.e. to erect a tower or similar structure) provided that it was to be fortified in the same manner as the existing chamber of Adam de Gesemuth (Jesmond) at Heaton, near Newcastle."

Original source is

• Calendar of Patent Rolls (1266-72) p178

(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 source are;

• King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol2 p372n262
  Coulson, C., 1979, 'Structural Symbolism in Medieval Castle Architecture' Journal of the British Archaeological Association Vol132 p88n52
  Bates, C.J., 1891, Border Holds of Northumberland (London and Newcastle: Andrew Reid) p8
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p403

Comyn, John , lord of Badenoch (d. c.1277)

Comyn, John , lord of Badenoch (d. c.1277)...He was in the English royal household in 1262, 1264, and 1265, and fought for Henry III at the battle of Lewes in 1264, where he was captured. The English records from 1260 to 1275 testify to the rich rewards available. Comyn received a confirmation of his important Tynedale lands in 1262 and permission to fortify his Northumberland manor house at Tarset in 1267. He was given numerous privileges in the royal forests, a yearly fee of £50, and in 1266 was promised (though never received) 300 librates of land ‘for his faithful service’ (CPR, 1258–66, 551). (Young)
He was a Scottish magnate and did significant service to the Scottish crown. Perhaps the licence was also about getting the recognition of his lordly status in this, English, outlying manor - his main estates being in Scotland. The detail may, and the specific requirement to not be stronger than Heaton, may have been there to mollify concerns of his English neighbours

Biographical source include;

• Alan Young, ‘Comyn, John , lord of Badenoch (d. c.1277)’, Oxford Dictionary of National Biography, Oxford University Press, 2004 [http://www.oxforddnb.com/view/article/6044, accessed 19 Nov 2007]
  

More details about licences to crenellate can be found here.

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