The Star Castle, St Mary's


Heritage Category: Scheduled Monument

List Entry Number: 1015671

Date first listed: 04-Mar-1997


Ordnance survey map of The Star Castle, St Mary's
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The building or site itself may lie within the boundary of more than one authority.

District: Isles of Scilly (Unitary Authority)

Parish: St. Mary's

National Grid Reference: SV 89883 10592, SV 89923 10645


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

In the later 15th century, the need to deploy and counter increasingly effective artillery began to revolutionise English fortification design. The medieval castle, a tower and curtain wall defence, evolved into the artillery castle, a strong stone defensive structure designed specifically to house heavy guns in gun towers, with limited garrison accommodation and sometimes accompanied by earthwork defences. They were usually sited to protect a harbour entrance, anchorage, town or similar feature. Artillery castles received their fullest expression in Henry VIII's maritime defence programme between 1539 and 1545 when they were deployed at strategic points along the east and south coasts of England. By then however new ideas developed in Italy were producing fundamental changes that came to dominate artillery defence design for the following three centuries. Low-lying earthen ramparts, faced by stone or brick and fronting a ditch, more effectively absorbed artillery fire while providing a platform for defensive artillery. Projecting angled bastions allowed defensive fire across all flanks and lines of approach. The new concepts proved highly adaptable, capable of application in the later 16th century to large scale defensive circuits around major towns or for creating smaller discrete fortifications. The 16th century fortifications on the Isles of Scilly illustrate these developments. On Tresco, the mid 16th century King Charles' Castle was one of the last artillery castles to be built, with its tower pierced by tiers of gun ports. The same defensive phase produced Harry's Walls on St Mary's, the earliest English artillery fort to deploy true angle bastions, though unfinished due to an inadequate site. When Government attention returned to the defence of the islands after the Spanish Armada of 1588, the new concepts in artillery defence were well-accepted and deployed on St Mary's at the Star Castle, an unusually small artillery fort employing a stone-faced earthen rampart; its size rendered it more appropriate to reduce the angle bastions to an overall star plan, an adaptation recommended in several contemporary military textbooks. The Star Castle survives well and, in conjunction with the complementary early phase of bastioned curtain wall crossing the Garrison neck, it forms one of less than ten recorded fortifications of the Elizabethan period surviving nationally. It was designed by one of the leading English military architects of the time, Richard Adams, and demonstrates clearly the concepts of artillery defence current in late 16th century England. The development of those concepts is well-displayed in an unusually close grouping by the presence of the King Charles' Castle on Tresco and the Harry's Walls fort on St Mary's. The importance of the Star Castle in the study of fortifications is further enhanced by its varied and evolving role as an integral part of the wider system of defences on the Garrison headland from the early 17th century onwards. The eventual domination of administrative and later non-military functions illustrates the impact of developing military strategies and technology on such fortifications, and some of the alternative uses which post medieval societies have deemed appropriate for such imposing structures.


Legacy Record - This information may be included in the List Entry Details.


The monument includes a late 16th century artillery fort, the Star Castle, built behind the northern crest of the Garrison, a large headland linked by an isthmus to the south west coast of St Mary's in the Isles of Scilly. The Star Castle is a Grade I Listed Building. This scheduling is divided into two separate constraint areas. The Star Castle contains a two-storey central house separated by a narrow passage from an encircling rampart faced by walling; the rampart's outer face forms an eight-pointed star in plan, giving the name of the fort. A covered entrance passage passes through the rampart on the north east. Outside the rampart a broad ditch is crossed by a stone causeway from the rampart entrance. Beyond the ditch are remains of an outermost rampart. The central house, excluded from this scheduling as detailed below, contained a hall, accommodation and service areas in the fort's original layout. It is nearly square in plan with sides oriented almost to the cardinal points and an angled projection rising up the centre of each wall. Its main door opens to the passage on the south of the east wall, with a service door opposite in the west wall. A first floor door in the west wall opens to a bridge across the passage to the rampart surface. The open passage around the central house is c.2m wide, largely cobbled with midline flagstones linking the main door of the house to the rampart entrance. Steps rise to the rampart surface at the south east and north west corners. On the north east, the open passage extends to a narrow covered entrance passage dog-legged through the rampart and ending at a square-headed stone doorway projecting slightly from the rampart. The doorway's moulded frame has low relief initials at the base of each jamb: on the right, `FG' of Sir Francis Godolphin, the islands' Governor when the fort was built; on the left, `RA' of Richard Adams, the fort's architect. The lintel bears the date `1593' and over the doorway, the outer face of an upper room includes a plaque bearing the initials `ER' of Elizabeth I. The dog-leg of the passage's east wall contains a deeply recessed square window, now blocked, directly facing the doorway from an eastern guardhouse behind. The inner end of the entrance passage was protected by a portcullis, evident from its wall slots, threshold recessed for four vertical bars and a chamfered outer arch. A stepped masonry structure above the slot's inner face carried the chains and winding gear for raising the portcullis. Several structures were built into the fabric of the rampart, opening off the passage around the house. These include a guardhouse to each side of the entrance passage at its inner end; the eastern has a blocked doorway in the rampart inner wall. The western guardhouse, an addition of c.AD 1700, is square with a pyramidal roof rising above the rampart surface. In its north west corner is a blocked opening to a tunnel under the northern rampart, joining a second tunnel on an angled course from a doorway at the centre of the passage's north side to a blocked doorway in the rampart's outer wall facing the ditch. These tunnels formed a sally port, intended to provide an alternative means of exit in times of siege. Other structures off the open passage include rooms forming service areas and stores beneath the centre of the west and south ramparts. That on the west is set back behind an open-fronted overhang in which the rampart's inner edge is supported by granite beams and props; the room has a blocked door and window facing the overhang. The room under the south rampart is subtriangular with a single doorway and small square window facing the passage. A third small room extends west from the south west corner of the passage. The rampart rises 2.6m from the passageway to a flattened upper surface, generally 6m-7m wide and almost level with the first floor of the central house. It is faced internally and externally by walls of irregular granite rubble, with more regular dressed slabs along most outer corners and with dressed and usually chamfered jambs, lintels and sills at openings. The inner wall ends as a low kerb along much of the rampart edge but at the four main corners it rises as a parapet with musket slits covering the open passage. The rampart's outer wall has a very steep slope, called a batter, over its lower levels towards the ditch, becoming vertical towards the top and projecting as a parapet over most of the rampart surface. Much of this parapet has an inner ledge beneath a row of musket slits but at each internal corner this is replaced by the blocking wall of a former gun embrasure, that on the NNE retaining its original paved platform. Each of the rampart's cardinal point corners contains a square building which formed barracks for the castle garrison, that on the north described in 1715 as the `Gunners Barrack' and that on the west extended by a later porch. On the rampart's south east corner is a small masonry sentry box; on the south west corner is a roofless and partly re-built masonry latrine chamber. In the north west corner is a flag platform, a level paved surface slightly higher than the parapet top and reached by stone steps on the east. A flagstaff is mounted against the south side of the platform. Built by 1715, this platform is later than the original parapet. In the north east corner, the room over the entrance doorway rises above the rampart surface as a small square building described in 1715 as the `Gunners Store'. Beside this room, the apex of the corner is occupied by a bellcote with masonry piers and a rounded arch, raised above the parapet on a small platform with access steps to the south. The rampart's outer wall descends into the inner side of the ditch, resting on bedrock in parts of the northern sector though its base is largely masked elsewhere by surface deposits. The ditch is c.5m wide and up to 3m deep, cut through the subsoil and, where exposed, into the bedrock. The base of the ditch is masked by deep silt deposits, confirmed during modern cable-laying operations. On the north east, a masonry causeway crosses the ditch from the doorway in the rampart face; it has vertical side walls, rising to a parapet whose inner ledges flank a cobbled surface with midline flags. At its outer end is a pyramidal flight of seven visible stone steps to a modern metalled drive beyond. Beyond the outer lip of the ditch, an earthen outer bank extends around much of the fort, though modern development and landscaping has levelled it on the south. The bank's profile varies but where clear of modern scrub it is generally c.7.5m wide and 1m high with a flattened top; a row of revetment blocks are visible along its inner edge adjoining the ditch on the west of the fort. A plan dated 1715 shows the bank gently merging with the natural slope beyond, a form called a glacis. On the north it is modified by the levelling cut for a modern road and by a modern levelled and revetted drive to the fort's entrance steps. The bank widens to give a raised flattened area north of the fort's flag platform, a feature considered to reflect the buried foundations of a former gun room recorded at this location on early 18th century plans. The scheduling also includes a cobbled hollow 32m beyond the SSW side of the fort's ditch and identified as one of several dewponds built in the mid 18th century to improve the fort's water supply. The hollow is ovoid, 9.8m north-south by 8.5m east-west, with sides sloping c.0.5m to a flattened base. Its surface is neatly lined by cobbles, c.0.1m across, with a kerb of larger slabs, c.0.3m across, on at least its north eastern periphery. The physical remains of this artillery fort are complemented by a wealth of historical sources regarding its construction, operation and context. The Star Castle was built in 1593-4 as the first part of a major upgrading and re-orientation of the islands' defences authorised by Elizabeth I to counter continued threats and raids from Spain following the failure of the Armada in 1588. Its construction was quickly followed, from c.1600, by a bastioned curtain wall to the east along the slope to the isthmus, creating a fortified headland whose defensive system was successively extended and strengthened over the next three centuries, during much of which the Star Castle remained the controlling element. In March to April 1646 the Prince of Wales, later Charles II, took refuge at the Star Castle during the Civil War; after 1648 the Star Castle became the last focus of Royalist resistance in England, surrendering in 1651. The Star Castle also served as a prison for several notable critics of the Government in the mid and later 17th century. In c.1700 extensive alterations took place, largely within the central house, and from 1834 the fort became the home of the Steward of the islands' lessee, Augustus Smith. During World War I, the fort housed army officers. With increased tourism on the islands the fort was converted to hotel use in 1933, most modification again involving the central house. In World War II, the fort was used to billet soldiers, with a signalling point on the roof of the central house. The central house, the modern garage by the causeway, all modern fixtures and fittings including the modern internal decoration of the rampart barracks, modern garden furniture, all modern stored materials, all modern service pipes and cables together with their fittings, existing trenches and supports are excluded from the scheduling. Also excluded from the scheduling is the modern metalled surface of the approach. The ground beneath all of these features 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: 15486

Legacy System: RSM


Books and journals
Adams, F, Adams, P, Star Castle and its Garrison, (1984)
Adams, F, Adams, P, Star Castle and its Garrison, (1984)
Saunders, A D, Fortress Britain, (1989)
Keystone Historic Buildings Consultants, Star Castle, St Mary's, Isles of Scilly, 1993, Unpubl report for EH; espec pp 45, 71
Keystone Historic Buildings Consultants, Star Castle, St Mary's, Isles of Scilly, 1993, Unpublished report for EH
p55; 1358-0/3/85; Star Castle Hotel, DNH, List of Buildings of Special Architectural or Historic Interest, (1992)
Parkes, C/CAU, Scilly SMR entries for PRN 7902 series, (1994)
Parkes, C/CAU, Scilly SMR entry PRN 7902.06 (formerly PRN 7654 pre-1994 revisn), (1994)
Saunders, A, Recent Fortifications and Defences Works Assessment, 1993, Unpubl report for English Heritage
Title: 1:2500 Ordnance Survey Map, SV 8715 Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Map; SV 8910 Source Date: 1980 Author: Publisher: Surveyor:
Young, A/CAU, Cable Laying Operations at the Star Castle, Isles of Scilly, 1993, Unpubl CAU watching brief report

End of official listing