"Licence for the mayor and commonalty of Oxford to fortify [the town] with a ditch (fossa) 200 feet wide, within its soil and liberty,and to hold the same as parcel of the town, at the same yearly fee farm.
Vacated by surrender and afterwards cancelled by command of the king, because granted and sealed at the time of the insurrection of the commons. "
Granted at London,
This licence was revoked
The town obtained licence to enlarge the ditch to a width of 200 ft., but the grant was cancelled after protests from Merton College, whose manor of Holywell extended up to the north wall.
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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