In 1330 July 23, Abbas et Conventus de Abyndon (Abbot and Convent of Abingdon Abbey) was granted, by Edward III, (In year 4 of his reign) a Royal licence to crenellate Abyndon (Abingdon Abbey)

"totum situm Abbati, videlicet tam domum Santi Johannis quam ecclesiam beati Nicholai infra precinctum ejusdem Abbati existentis muro, "

Granted at Woodstock, by privy seal.

all of the site of their abbey, including the hospital of St John and the church of St Nicholas with the precinct,

Original source is

• Calendar of Patent Rolls (1327-30) p547

(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;

• Coulson, C., 1982, 'Hierarchism in Conventual Crenellation' Medieval Archaeology Vol26 p88, 94
  Page, Wm. and Ditchfield, P.H. (eds), 1907, 'Houses of Benedictine monks: The abbey of Abingdon' VCH Berkshire Vol2 p51-62
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p278, 409

More details about licences to crenellate can be found here.

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