"Quo facto idem rex concessit firmare unam de turribus suis de castro Lincoln(ie) de qua comes habebit dominium"
Although this document has been considered by some as a licence to crenellate the current opinion rejects this as a licence to crenellate.
An agreement was made, following the war of the Anarchy, for Earl Ranulf to hold a certain tower, previously fortified by the Countess Lucy. Not, in a meaningful sense, a licence to crenellate although has been called this by some.
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;
Ranulf (II) [Ranulf de Gernon], fourth earl of Chester (d. 1153), magnate. The countess Lucy of Bolingbroke was his mother and had inherited considerable lands in Lincolnshire from her father but had to cede most of these to Henry I. Ranulf ceased Lincoln castle from Stephen in 1140. His involvement in the Anarchy was mainly about his personal ambition and grievances. The naming of this tower after his mother suggests a hereditary claim underlay his seizure of the castle.
Biographical source include;
More details about licences to crenellate can be found here.
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