"for their better safety from night attacks in passing from their houses to the said church, to enclose the precinct of the said church with a wall, 12 feet high, in suitable places, at Pottergate street and at the street leading from the high road of the bailey (ballii) to the Estegate with the two adjoining lanes on the north side: the said wall to be provided with sufficent gates with locks, to the custody of which they and their successors shall appoint one of their body to close them at dusk and open them again before sunrise."
Granted at Westminster,
The Dean and Chapter received licenses to crenellate the Cathedral. The first for a 12 foot wall (issued 1285 and repeated 1316) the second to raise the wall and add turrets (issued 1318).
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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