The Gatehouse website record of a licence to crenellate for Portland granted on 1259 Feb 7

Licence for Richard de Clare, earl of Gloucester and Hertford, to fortify (firmare) the island of Portlaund with stone and lime and to crenellate it in the manner of a castle, as he thinks best.
By the bishop of Worcester, R. earl of Gloucester, Peter de Sabaudia, R. earl of Norfolk marshal of England, Hugh le Bigod justiciary of England, John Maunsel treasurer of York, and others of the council. (CPR)

Richardus de Clar., Comes Gouc. et Hertford ... insulam de ... Portland. (Turner and Parker)

Granted at Westminster. Grant by the bishop of Worcester, R. earl of Gloucester, Peter de Sabaudia, R. earl of Norfolk marshal of England, Hugh le Bigod justiciary of England, John Maunsel treasurer of York, and others of the council..

Comments

King writes "in the same terms as the last (1256 qv), but to Richard de Clare, Earl of Gloucester". in 1270 Gilbert de Clare, son of Richard was forbidden from proceeding with the fortification of the island, and ordered to destroy anything that he had built for this purpose. It is generally presumed that Rufus castle is the site of any work that may have resulted from this licence and any remains that may date from the period exist only at foundation level.

Original source is;

Lyte, H.C. Maxwell (ed), 1910, Calendar of Patent Rolls (1258-66) p. 11 online copy

(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., 1994, 'Freedom to Crenellate by Licence - An Historiographical Revision' Nottingham Medieval Studies Vol. 38 p. 131
King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 132n33
Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol. 3 part 2 p. 402 online copy

Clare, Richard de, sixth earl of Gloucester and fifth earl of Hertford (1222–1262)

Clare, Richard de, sixth earl of Gloucester and fifth earl of Hertford (1222–1262), magnate. Richard was far too powerful a lord to insult by not giving a licence but Portland is also far from his real power base of Wales and the Marches. The king's real solution to an over powerful lord was not a uninforcable restriction on castle building but, as happen to the de Clares, a taking into the kings hads of his lands on his death whilst Gilbert, the hier, was under age. The licence possibly has more to do with the recent change of ownership following the death of the previous owner, Aymer Lusignan, bishop of Winchester. Gilbert was married to Alice Lusignan, Aymer's niece, in 1254. The 1270 restriction was part of a possession dispute between Gilbert and Henry III, half brother to Aymer, and has much more to do with stopping the establishment of ownership rights through the building of a home rather than the prevent of any military base.

Biographical source include;

Michael Altschul, 2004, ‘Clare, Richard de, sixth earl of Gloucester and fifth earl of Hertford (1222–1262)’ 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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