The Gatehouse website record of a licence to crenellate for Hartley Castle granted on 1353 Oct 4

Licence for Thomas de Musgrave to crenellate the dwelling-place of his manor of Harcla, situated near the march of Scotland, which has been often burned and destroyed by the Scots in times past. By K. (CPR)

Thomas de Musgrave ... mansum manerii ... Harcla (quod prope Marchiam Scociae situatur et per Scotos inimicos nostros saepius ante haec tempora combustum extitit et destructum). (Turner and Parker)

Granted at Westminster. Grant by King.

Comments

Thomas de Musgrave received a licence to crenellate in 1353 because it had frequently in the past been burnt by the Scots.
Here both Scottish raids and legal disputes show the need to fortify houses, but not a need to obtain a licence to crenellate. The real threat seems to have been family and neighbours, rather than scots. Marmaduke de Constable, who was sheriff of Yorkshire directly following both times Thomas held the post, had obtained a licence to crenellate just 20 months before.

Original source is;

Lyte, H.C. Maxwell (ed), 1907, Calendar of Patent Rolls (1350-54) p. 493 online copy

(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. Licentia is best translated as 'freedom to' not 'permission'.)

Significant later sources are;

Emery, Anthony, 1996, Greater Medieval Houses Vol. 1 (Cambridge) p. 263
King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 2 p. 496n10
Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol. 3 part 2 p. 416 online copy

Musgrave, Thomas, Lord Musgrave (b. in or before 1307, d. c.1385)

Sir Thomas de Musgrave (b. 1302, d.c. 1385) of Harcla Castle, Soldier, Warden of the West March, knighted at the battle of Nevilles Cross in 1346, Sheriff of Yorkshire 1360 and 1363-65, Sheriff of Westmorland 1342,Governor of Berwick then York, numerous other official posts and almost continuous official employment. Lord Musgrave from 1350.
Musgrave's first wife was Margaret, daughter and coheir of William Roos, of Youlton, Yorkshire. Their son and heir, Thomas, was born about 1338. After Margaret's death Musgrave married Isabel, widow of Robert, Lord Clifford, and daughter of Maurice, Lord Berkeley, between May 1344 and June 1345. On her death in 1362, he sought to exclude his stepson Roger de Clifford from Isabel's Yorkshire estates at Skipton. Clifford's attempts to recover these through litigation in 1366 led to disorder in Westmorland. Musgrave and his followers broke into and poached from Clifford's park at Murton in 1368. Clifford responded by besieging Musgrave's manor house at Hartley in 1370, which Musgrave had been given licence to crenellate in 1353 due to repeated Scottish attacks. (Baxter)

Biographical source include;

R. R. Baxter, Sept 2004, ‘Musgrave, Thomas, Lord Musgrave (b. in or before 1307, d. c.1385)’ Oxford Dictionary of National Biography (Oxford University Press)online edn, Jan 2008 online copy (subscription may be needed)

More information about licences to crenellate can be found here.

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