"Grant, of Special Grace, to Robert de Corby, king's yeoman, that within his manor of Boghton Malherbe, co. Kent, may fortify a certain place with a wall of stone and mortar, crenellate it and make a fortress (fortalicium) thereof, and may hold the said fortress so made to him and his heirs without let or hindrance of the king and his heirs or any their ministers; grant also to the said Robert and his heirs of free warren in all their demense lands within the manor aforesaid."
Granted at Windsor, by privy seal.
A licence was also granted in 1313.
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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