In 1376, Prior and Convent was possibly granted, by Edward III, a Royal licence to crenellate (Gisborough Priory)

There is insufficient evidence to be certain about this possible licence to crenellate.

Jackson writes "In 1376 a licence to crenellate was reputedly issued to the 'Prior and Convent to enclose and embattle the walls of the Priory'. This wall and a ditch enclosed about ninety acres, and had two gateways." This is not a confusion with the enrolled 1344 licence which Jackson also records.

Significant later source are;

• Jackson, M.J., 1996, Castles of Durham and Cleveland (Carlise) p32-3

More details about licences to crenellate can be found here.

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