In 1307 April 24, Mathias de Monte Martini (Mathew de Mount Martin) was granted, by Edward I, (In year 35 of his reign) a Royal licence to crenellate manse of Burn [Burne] (Westbourne)

"April 24, 1307, For Matthew de Mount Martin. The King to all bailiffs, &c., greeting. Know ye that of our special grace we have granted and given license, on behalf of ourselves and our heirs, as much as in us lies to our beloved and faithful Matthew de Mount Martin, to enclose and crenellate his manse [mansum suum] of Burn, in the county of Sussex, with a wall of stone and lime, and may hold that manse so enclosed and crenellated for himself and his heirs for ever without penalty or impediment from us or our heirs, justiciaries, sheriffs, or others, our bailiffs or officers whosoever. In witness whereof, &c. Dated Carlisle, 24 April"

Granted at Carlisle, by privy seal.

In 1307 Mathew de Mount Martin was granted a licence to crenellate his manse of Burn (now Westbourne). The site has not been located.

Original source is

• Calendar of Patent Rolls (1301-7) p522

(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, 2006, Greater Medieval Houses Vol3 (Cambridge) p439
  Blaauw, William Henry, 1861, 'Royal Licenses to Fortify Towns and Houses in Sussex' Sussex Archaeological Collections Vol13 p104-117
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p405

More details about licences to crenellate can be found here.

Please let me know if you see any errors, can add information or can otherwise help to improve this resource. Contact me