Ennor Castle, Old Town, St Mary's


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:


Ordnance survey map of Ennor Castle, Old Town, St Mary's
© Crown Copyright and database right 2019. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2019. All rights reserved. Licence number 102006.006.
Use of this data is subject to Terms and Conditions.

The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1014994 .pdf

The PDF will be generated from our live systems and may take a few minutes to download depending on how busy our servers are. We apologise for this delay.

This copy shows the entry on 22-Oct-2019 at 19:46:28.


The building or site itself may lie within the boundary of more than one authority.

Isles of Scilly (Unitary Authority)
St. Mary's
National Grid Reference:
SV 91418 10350

Reasons for Designation

A shell keep castle is a masonry enclosure extending around the top of raised mound which is often, but not always, derived from an earlier fortification; the enclosure is usually rounded but other shapes are known. A shell keep is relatively small, normally between 15m and 25m across, and is seldom more than one storey high. Unless supplemented by excavated evidence, few traces of internal buildings are generally found as they were usually of wood, only rarely being replaced in stone. Shell keeps were built over a period of about 150 years from the end of the 11th century to the mid 13th century; most were built in the 12th century and provided strongly fortified residences for the king or leading families. Shell keep castles are widely dispersed throughout England, with a marked concentration in the Welsh Marches and with a distribution extending into Wales and to a lesser extent into Scotland. They are a rare class of monument, with 71 recorded examples nationally, of which only one is situated in the Isles of Scilly. They display a considerable diversity of form, with no two examples exactly alike. Along with other contemporary forms of castle, they are major medieval monuments which, belonging to the highest levels of society, frequently acted as administrative centres and formed the foci for developing settlements. Consequently they form valuable sources of information on medieval society, its settlement and trading patterns, and on medieval defensive methods.

Ennor Castle survives in recognisable form despite dismantling of much of the keep wall. Sufficient evidence survives to determine the overall ground plan while the interior has not been archaeologically excavated or redeveloped and will retain buried evidence for its internal features. With the broadly contemporary church and quay at Old Town, it forms one of the three major and surviving elements of the main secular settlement on Scilly during the medieval period. Its location relative to the settlement and its historically recorded tenure demonstrate the role and setting of shell keep castles. The sequence of occupation and decline of Ennor Castle also illustrates the interdependence of such castles with their wider settlement context. Its decline shows particularly clearly the impact of change at national level in the 16th century. Ennor Castle is the only medieval castle on the Isles of Scilly. It is also the earliest element in an almost continuous sequence of fortifications on the islands, which extends to the end of World War II and which is itself nationally very rare in terms of completeness and quality of survival.


The monument includes a small shell keep castle known as Ennor, or Old Town, Castle in the present village of Old Town on the south coast of St Mary's in the Isles of Scilly. The castle occupies a small but prominent knoll on the east side of the broad Lower Moors valley behind Old Town Bay. The knoll has a semicircular rocky scarp facing west, up to c.10m above the valley floor, from which the knoll slopes steeply to more gently sloping land to the east. The castle encompassed the knoll with a subrectangular keep wall, now partly dismantled. An outer earthwork bank is visible along the foot of the slope and traces of walling indicate an adjacent enclosure south east of the knoll. The walls of the sub-rectangular keep no longer survive in their entirety above ground level. The wall survives above ground on the north west and part of the west side, where it is c.1m thick, of coursed rubble. Its footings vary in height with irregularities in the knoll, and the wall's height thus also varies, averaging 1m above interior ground level but reaching 2m high in places. Elsewhere, the line of the wall is now marked by earthwork banks between 2m and 4.5m wide and 1m to 1.5m high along the south west and east sides, and by a wider spread of dense rubble on the south east side. The keep's walls defined a subrectangular internal area measuring 22m north east-south west by up to 17m north west-south east, rounded at the south west end and squared at the north east. The interior of the castle has only a limited level area behind the south west end, beyond which the surface slopes fairly steeply. Internal buildings, typically of timber within small shell keep castles, have left no visible remains above ground level. An outer earthwork extends along the foot of the slope north east of the keep. It survives as a slight bank up to 0.25m high. Also beyond the keep, a short exposure of walling extends from the southern end of the knoll's outcrops, implying an adjacent enclosure south east of the keep. The wall is built of coursed rubble, 0.5m high and is visible over 2m before becoming covered by later deposits. The wall runs along slightly elevated land extending south east from the knoll; this area has been subject to relatively recent gardening and the survival of earlier features is unknown. Surviving historical sources add to our knowledge of Ennor Castle. The earliest reference to Ennor Castle is in a deed of AD 1244, by which time Ennor (or `La Val' in Anglo-Norman documents) had been the main settlement on St Mary's for some time. By 1306 Ranulf de Blanchminster held the castle in return for the provision of 12 men-at-arms to maintain the peace and the payment of an annual tribute to the king of 6s 8d or 300 puffins at Michaelmas, a tribute whose actual payment was always recorded in money. A royal licence to crenellate (ie to defend) the castle was granted to Ranulf in 1315 but in 1337, the castle along with the rest of Scilly, was included in the lands of the newly created Duchy of Cornwall. In c.1540, the King's Antiquary, John Leland, described the castle as `a meately strong pile'. It still formed an effective fortification, and in May 1554 a survey records that Ennor Castle was armed with cannon. The fortunes of the castle and its adjacent settlement were finally eclipsed when the fortification of Scilly was revised to serve national defensive considerations in the late 16th century, when the Star Castle was built. At the same time the focus of settlement and trade also moved to St Mary's Pool, leaving Ennor Castle redundant and Ennor's town and harbour in decline. A survey of 1652, refers to the settlement at St Mary's Pool (the present Hughtown) as `Hue or New Towne', while Ennor was termed `Old Town'. By local tradition, the castle was dismantled to build the Star Castle, but in view of the distance it is more likely that Ennor Castle was progressively dismantled to provide building stone for more local purposes in Old Town. The modern water storage and header tanks, their pipes and fittings and the pipe-support blocks are excluded from the scheduling but the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Books and journals
Bowley, R L, The Fortunate Islands: A History of the Isles of Scilly, (1968)
Ratcliffe, J, The Archaeology of Scilly, (1989)
Ratcliffe, J, Scilly's Archaeological Heritage, (1992)
Thomas, C, Exploration of a Drowned Landscape, (1985)
Saunders, A D, 'Cornish Archaeology' in Harry's Walls, St Mary's Scilly; a new interpretation, , Vol. 1, (1962), 85-91
In conversation on 23/11/1993, Tradition told to MPPA by castle's owner, Mr Gren Hardern, (1993)
Keystone Historic Buildings Consultants, Star Castle, St Mary's, Isles of Scilly, 1993, Unpublished report for EH
Rees, S E, AM 7 scheduling documentation for SI 990, Remains of Old Town Castle, 1975,
Release 00, January 1989, Leach, PE, Monument Class Description 'Shell Keeps', (1989)
Title: 1:2500 Ordnance Survey Map; SV 9110 Source Date: 1980 Author: Publisher: Surveyor:
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7544, (1988)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

Your Contributions

Do you know more about this entry?

The following information has been contributed by users volunteering for our Enriching The List project. For small corrections to the List Entry please see our Minor Amendments procedure.

The information and images below are the opinion of the contributor, are not part of the official entry and do not represent the official position of Historic England. We have not checked that the contributions below are factually accurate. Please see our terms and conditions. If you wish to report an issue with a contribution or have a question please email En[email protected].