In 1434 Nov 6, Rolandus Lenthall, miles, et Lucia uxor ejus (Sir Rowland Lenthall and his wife) was granted, by Henry VI, (In year 13 of his reign) a Royal licence to crenellate Hampton Richard [Hampton Rychard] (Hampton Court, Hope under Dinmore)

"Licence, by advice of the council, for Roland Lentall, knight, and Lucy his wife, to crenellate, turrellate and embattle their manor (mansum) of Hampton Rychard, co. Hereford, and make a fortalice there; also to impark 1,000 acres of land."

Granted at Westminster, by privy seal.

King writes "licence to make a fortalice."

Original source is

• Calendar of Patent Rolls (1429-36) p446

(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;

• King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p217n67
  Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol3 pt2 p377, 422

More details about licences to crenellate can be found here.

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