"Licence for Richard de Clare, earl of Gloucester and Hertford, to fortify (firmare) the island(insulam de) of Portlaund with stone and lime and to crenellate it in the manner of a castle, as he thinks best."
Granted at Westminster, 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..
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
(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;
More details about licences to crenellate can be found here.
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