In 1406 Jan 15, Johannes de Stanley, miles was granted, by Henry IV, (In year 7 of his reign) a Royal licence to crenellate Lyverpole (Liverpool, Stanley Tower)

"Licence for the king's knight John de Stanley, steward of the household, to crenellate a house which he has built in the town of Lyverpole co. Lancaster.
quandam domum quam ipse de Lyverpole"

Granted at Westminster, by privy seal.

Original source is

• Calendar of Patent Rolls (1405-8) p207

(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;

• Emery, Anthony, 1996, Greater Medieval Houses Vol1 (Cambridge) p263
  King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p251n36
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p421

Stanley, Sir John (c.1350–1414)

Stanley, Sir John (c.1350–1414), soldier and administrator. Stanley's career reached its peak in the aftermath of the Percys' rebellion. In 1405 he was rewarded with a grant of the lordship of the Isle of Man, forfeited by Henry Percy, earl of Northumberland, which gave his lineage a crown. Around the same time he became steward of the king's household, and secured election as a knight of the Garter. (Bennett)

Biographical source include;

• Michael J. Bennett, ‘Stanley, Sir John (c.1350–1414)’, Oxford Dictionary of National Biography, Oxford University Press, 2004 [http://www.oxforddnb.com/view/article/26275, accessed 1 Feb 2008]
  

More details about licences to crenellate can be found here.

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