"quandam domum per ipsum ut dicit apud manerium suum de Wirkyngton in Com. Cumb. juxta Marchiam Scotiae muro de petro et calce edificatam firmare et kernellare"
Granted at Westminster, by privy seal.
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;
The Curwen's were a knightly family with a long history of military service in the north. Gilbert was warden of the west march at this date. Workington had been held by the family from the early C13, so the licence was for a rebuilding or expansion of an existing home which, in this area, was probably fortified already.
Neither were the gentry altogether exempt for in 1403 Sir Gilbert Curwen, his son Sir William and two younger sons all died of the fell disease. (Curwen)
Biographical source include;
More details about licences to crenellate can be found here.
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