St Michaels Mount Castle

Has been described as a Possible Timber Castle (Motte), and also as a Possible Masonry Castle, and also as a Certain Artillery Fort, and also as a Certain Fortified Ecclesiastical site

There are masonry footings remains

NameSt Michaels Mount Castle
Alternative Names
Historic CountryCornwall
Modern AuthorityCornwall
1974 AuthorityCornwall
Civil ParishSt Michaels Mount

It is generally accepted that the summit of the Mount was first provided with stone-built defensive structures at the end of the 12th century when, in 1193, "Henry de Pomeray took possession... in John's name, fortified it and expelled the monks" (Fletcher 1951, 24). He, or Richard I, after his release and Pomeray's suicide, could well have been responsible for the main elements of the castle's layout, in particular the square towers (typically 12th century) at each end of the main western entrance range (91531) and the lesser square towers behind them to the SE (91532 and 91533). These features form the core of the castle and have the priory (91515) safely behind them although even this was fortified, the church tower battlemented and the court walls crenellated. Although post-medieval and 19th century residential improvements have substantially altered the rectangular towers and the range, more survives of the medieval castle than is usually thought. The massive buttress projecting from the southern end of the outer western face of the principal northern tower was probably part of a substantial entrance or gate-house. The well-preserved flight of steps (91530) would have run through it. To the south of these steps was a large building (91529), now almost completely levelled, a possible third and outer gatehouse. Further west still are the footings of a well- built curtain wall, part curvilinear, part rectilinear (91550). Other fragments of probably medieval curtain wall survive to the north, east and south-east of the castle (91551-91553). Although the Mount returned to the peaceful activities of the priory after Pomeray's removal it seems that a military role, but not necessarily a garrison as such, was maintained; the priory (and presumably Mont St Michel, the parent Abbey) was aware that it needed to be able to protect itself

The state too would have benefitted from the strategically useful Mount being defensible and in 1338, while preparing for war with France, King Edward III dismissed Ralph Bloyan from the castle and replaced him by Reginald de Boterels (Botreux) and John Hamly, Sheriff of Cornwall (Taylor 1932, 116). As it was the Mount saw no further military action until the later 15th century. In 1472 John de Vere, the Lancastrian Earl of Oxford, seized the mount by entering with either 80 or 400 men (accounts differ), disguised as pilgrims. The siege which eventually saw Oxford out was intense (see Taylor 1932) and was probably the spur which led to the increased fortification of the Mount including the throwing up of breastworks (91554) around its cliffs and the placing of cannon at its summit. Adaptations of the castle's defences would have continued through the centuries, right down to the Napoleonic Wars when several batteries were placed at the summit and around the island. The core of the castle, however, seems to have remained largely unaltered with the only major change the abandonment of the western gates and buildings during, or more likely, some time before the Civil War. (National Trust HBSMR)

Gatehouse Comments

Only traces of the structures predating the Tudor period survive.

- Philip Davis

Not scheduled

This is a Grade 1 listed building protected by law

Historic England Scheduled Monument Number
Historic England Listed Building number(s)
Images Of England
Historic England (PastScape) Defra or Monument number(s)
County Historic Environment Record
OS Map Grid ReferenceSW514298
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  • Purton, P.F., 2010, A History of the Late Medieval Siege: 1200-1500 (Woodbridge: The Boydell Press) p. 302
  • Duffy, Michael, 1999, 'Coastal Defences and Garrisons 1480-1914' in Kain, R. and Ravenhill, W., Historical Atlas of South-West England (University of Exeter Press) p. 158-60
  • Higham, Robert A., 1999, 'Castles, Fortified Houses and Fortified Towns in the Middle Ages' in Kain, R. and Ravenhill, W., Historical Atlas of South-West England (University of Exeter Press) p. 136-43
  • Salter, Mike, 1999, The Castles of Devon and Cornwall (Malvern: Folly Publications) p. 38-41
  • Pettifer, A., 1995, English Castles, A guide by counties (Woodbridge: Boydell Press) p. 22-23
  • Spreadbury, I. D., 1984, Castles in Cornwall and the Isles of Scilly (Redruth)
  • King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 75-6
  • Fry, P.S., 1980, Castles of the British Isles (David and Charles) p. 290
  • Price, M. and H., 1980, Castles of Cornwall (Bossiney Books) p. 54-74
  • Renn, D.F., 1973 (2 edn.), Norman Castles of Britain (London: John Baker) p. 306
  • Pevsner, N. revised by Enid Radcliffe, 1970, Buildings of England: Cornwall (Harmondsworth) p. 175-7
  • Fletcher, J.R. edited and completed by Dom John Stephan, 1952, A history of St Michael's Mount (generally religious history)
  • Taylor, Thomas, 1932, History of St Michael's Mount (Cambridge) (history only)
  • Oman, Charles W.C., 1926, Castles (1978 edn Beetham House: New York) p. 116-122
  • Harvey, Alfred, 1911, Castles and Walled Towns of England (London: Methuen and Co)
  • Mackenzie, J.D., 1896, Castles of England; their story and structure (New York: Macmillan) Vol. 2 p. 13-5 online copy
  • Timbs, J. and Gunn, A., 1872, Abbeys, Castles and Ancient Halls of England and Wales Vol. 1 (London) p. 497-9 online copy
  • Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol. 3 Part 2 p. 361 online copy
  • Lysons, D. and S., 1814, Magna Britannia Vol. 3 Cornwall p. 137-42 online transcription
  • Buck, Samuel and Nathaniel, 1774, Buck's Antiquities (London) Vol. 1 p. 29-30
  • Grose, Francis, 1787, Antiquities of England and Wales (London) Vol. 8 p. 29-42 online copy


  • Camden, Wm, 1607, Britannia hypertext critical edition by Dana F. Sutton (2004)
  • Chandler, John, 1993, John Leland's Itinerary: travels in Tudor England  (Sutton Publishing) p. 84
  • Toulmin-Smith, Lucy (ed), 1907, The itinerary of John Leland in or about the years 1535-1543 (London: Bell and Sons) Vol. 1 p. 320 online copy; Vol. 4 p. 116 [online copy >]


  • Pool, P.A.S. (ed), 1975, ' 'The ancient and present state of St Michael's Mount, 1762” ' Cornish Studies 3 p. 29-47
  • Brown, R. Allen, 1959, 'A List of Castles, 1154–1216' English Historical Review Vol. 74 p. 249-280 (Reprinted in Brown, R. Allen, 1989, Castles, conquest and charters: collected papers (Woodbridge: Boydell Press) p. 90-121) view online copy (subscription required)
  • Hussey, 1924, Country Life Vol. 56 p. 672-9, 714-20
  • Peter, T.C., 1900, 'Notes on St. Michael's Mount' Journal of the Royal Institution of Cornwall Vol. 14 p. 221-46 online copy
  • Leyland, 1897, Country Life Vol. 2 p. 42-4 (slight)
  • St Aubyn, 1861, Exeter Diocesan Architectural Society Vol. 6 p. 259-69 (slight)

Guide Books

  • Trinick, M., 1983, St Michael's Mount, Marazion, Cornwall: The Tour of the Castle
  • John St Aubyn, 1978, St Michael's Mount Illustrated History and Guide (Beric Tempest)
  • Wake, Joan, 1934, A Guide to St Michael's Mount with a summary of its history from legendary times

Primary Sources

  • Stubbs, W. (ed), 1869, Chronica Magistri Rogeri de Houedene (Rolls Series 51) Vol. 3 p. 237
  • Stenton, D.M. (ed.), 1927, The Great Roll of the Pipe for the fifth year of the reign of King Richard the First, Michaelmas 1193 (Pipe Roll 39) (Pipe Roll Society Publications 41)
  • Rickard, John, 2002, The Castle Community. The Personnel of English and Welsh Castles, 1272-1422 (Boydell Press) (lists sources for 1272-1422) p. 142-3
  • Henry VIII’s coastal defence maps
  • B.M. Harleian MS. 1326 (Survey of 1623) British Library collection information