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Summary

Harry's Walls, the remains of an unfinished fort on Mount Flagon begun in 1551 but abandoned.

Protected Status

• Scheduled Monument 15403: HARRY'S WALLS UNFINISHED 16TH CENTURY ARTILLERY CASTLE AND ADJACENT PREHISTORIC STANDING STONE AT MOUNT FLAGON, ST MARY'S

Other References/Statuses

• National Monuments Record: SV 91 SW 25
• National Record of the Historic Environment to Historic Environment Records data transfer
• National Record of the Historic Environment: 304019
• OS No. (OS Quarter-sheet and OS No.): SV91SW 25
• Primary Record No. (1985-2009): 7568
• SMR No. (OS Quarter-sheet and SMR No.): SV91SW 41

Monument Type(s):

• ARTILLERY CASTLE (16th Century - 1551 AD to 1554 AD)
• REFUSE DISPOSAL SITE (16th Century to 18th Century - 1560 AD? to 1800 AD?)

Full description

An unfinished artillery castle dating to the mid-16th century, known as 'Harry's Walls', situated on the summit of Mount Flagon, overlooking St Mary's Pool. The design of the fort reflected latest military thinking, incorperating angled bastions allowing for flanking fire, reflecting ideas imported from Italy and comparable to broadly contemporary castles built in nelgand, such as Yarmouth, although this would have been the first fortification provided with entirely with angled bastions (1, 2, 7). The fortress was never completed, and whilst this is often attributed to poor placement, this it is more likely to be due to a nationwide cut back on military spending (1). A brew house and mill were to be built, to serve the fort at a fresh water pool below Mount Flagon which Saunders (2) identifies as a low lying marshy area described as a source of fresh water by Borlase (3).

The first reference to the monument occurs in the Acts of the Privy Council of England for the 27th of May 1551, in which a letter to John Kelligrewe concerning the lead for the construction of a new fortress on St Marys is mentioned (1, 4). A plan of the intended defences dating to the 1550s is held in the collections of Hatfield House, although notably the legend of the plan indicates that construction had already been started at the time of its creation (1, 5, 6). Harry's Walls is discussed by Borlase in 1756 (3), by which time the site had aquire dits present name. He describes a curtain surviving with a bastion at either end, with the northern bastion containing cells to store mines or as lodgings. He incorrectly attributes the construction of the fort to Henry VIII's reign, at states poor location as the reason construction was abandonned. The incomplete fortress is illustrated on Spence's 1792 map of the Isles of Scilly, where it is named Harry's Walls (8). Troutbeck discusses the monument (9), but copies Borlase' account almost verbatim. The walls are illustrated in the 1889 first edition 6" OS map, but not named (10).

Clearance of site and consolidation of the masonry by the MoW (5, 11) (this is a Grade II Listed Building and a Guardianship site) showed that only a small part of the fort had been built before abandonment. The amount of masonry work completed could not be determined because of robbing, but a rock-cut ditch had been started on the north side. Rubbish from the bastions included C17 and C18 pottery.

The OS field worker (12) describes the remains of two bastions and curtain wall connecting, the south side being the only side of the square to be completed. A rock-cut ditch indicates the position of the projected north west side. The curtain and bastion wall faces have been largely robbed of their dressed granite blocks. The curtain wall is 27m long and, about midway along its length, gives an indication where the inner ground level would have been had a courtyard been completed. Faces of bastions average 21m in length, with a maximum height of 2.3m. The narrow passage way leading from the bastion to the courtyard is well preserved, but one from the west bastion has been severely damaged and masonry mixed with tumbled remains of flankers/orillions which connected the bastion faces to the ends of the curtain wall.

The site was visited in 1988 (13) and found to be as described by the OS fieldworker. The average height inside the curtain wall was 1.0m; the passage into the south bastion was 1.2m wide, with walls up to 1.4m high either side. The walls were faced with blocks averaging 0.5m long and 0.4m deep and 0.2m high, their outer sides squared; and filled with small to medium rubble (average 0.4m square by 0.2m). Natural rock was exposed in places inside the bastions and in the foundations of the walls. The rock-cut ditch averaged 1.2m deep and 8.0m across at ground level, 5.0m across its base.

The site was surveyed in 2008-10 (14, 15). The slight earthworks in the interior show that construction proceeded further than the masonry remains suggest. Part of a right-angled cut may be a wall footing and other earthworks possibly represent attempts to level the site.

In 2010 a watching brief undertaken in the property to adjacent to the fort to the west did not identifiy any archaeological features (17).

In 2013 a watching brief was undertaken in the immediate vicinity of the monument and within the scheduled area as part of the installation of a new electricity post (16). No archaeological features were encountered.

The monument was included in the Schedule on 11/5/1950, was confimed on 9/10/1981, and the scheduling was amended on 1/4/1994.

Harry's Walls, Mount Flagon, St Mary's, Isles of Scilly (Collection). SCO29955.

Isles of Scilly: Various Sites (Collection). SCO29954.

Ordnance Survey, 1976, OS76/F164/90 (Aerial Photograph). SCO29949.

Ordnance Survey, 1976, OS76/F164/91 (Aerial Photograph). SCO29950.

Ordnance Survey, 1978, OS78/F12/4 (Photograph). SCO29952.

Ordnance Survey, 1978, OS78/F12/5 (Photograph). SCO29953.

ENGLISH HERITAGE, 1998, The English Heritage visitors' handbook, 77 (Booklet). SCO29951.

ENGLISH HERITAGE, 2004, Heritage Unlocked: Guide to free sites in Cornwall and the Isles of Scilly, 72-73 (Booklet). SCO29764.

<1> Bowden, M and Brodie, A, 2011, Defending Scilly, 10-14 (Bibliographic reference). SCO29932.

<2> Saunders, AD, 1962, Harry's Walls, St Mary's, Scilly: a New Interpretation, VOL 1, 85-91 (Article in Journal). SCO4321.

<3> Borlase, W, 1756, Observations on the Ancient and Present State of the Islands of Scilly, 15-17 (Bibliographic reference). SCO2883.

<4> Acts of the Privy Council of England, 27 May 1551, 282 (Unedited Source). SCO29946.

<5> O'Neil, BH St J, 1961, Isles of Scilly MOW Guide, 26-28 (Bibliographic reference). SCO4042.

<6> UNKNOWN, 1550s, Plan of proposed fortifications at Harry's Walls, St Marys (Graphic material). SCO29947.

<7> Colvin, HM et al., 1982, The History of the King's Works, Volume 4 : 1485-1660 (Part 2), 587-593 (Bibliographic reference). SCO29948.

<8> SPENCE, G, 1792, SURVEY OF THE SCILLY ISLES (Unedited Source). SCO5644.

<9> Troutbeck, J, 1796, Survey of the Ancient and Present State of the Scilly Islands, 104-105 (Bibliographic reference). SCO4965.

<10> Ordnance Survey, 1880s, 1st Edition 6 Inch Map, Cornwall LXXXVII.SE (Cartographic materials). SCO4049.

<11> DOE, Listed Building Description (original DOE), NOV 1954, 15, 6/18 (Bibliographic reference). SCO5173.

<12> Field Investigator's Comments, OS/JGB 1978 (Survey). SCO29739.

<13> Field Investigator's Comments, CAU/Parkes, C 1988 (Survey). SCO29739.

<14> Field Investigator's Comments, HE/Bowden, M and Brodie, A 2009 (Survey). SCO29739.

<15> Bowden, M, 2011, Isles of Scilly Military Defences, 1540-1951: Earthwork Sites and Minor Features, 24 (Cornwall Event Report). SCO25530.

<16> Thorpe, C, 2013, Harry's Walls, St Mary's, Scilly - Electric Pole Replacement: Archaeological Watching Brief (Cornwall Event Report). SCO25528.

<17> Sawyer, K, 2011, Harry's Walls, St Mary's, Isles of Scilly - Archaeological Recording (Cornwall Event Report). SCO24949.

Sources / Further Reading

Associated Finds: none recorded

Associated Events

• ECO3818 - Harry's Walls, St Mary's, Isles of Scilly: Watching Brief (Ref: 146222)
• ECO3944 - Harry's Walls, St Mary's, Isles of Scilly: Desk-Based Assessment, 1962
• ECO3819 - Isles of Scilly Military Defences, 1540-1951 (Ref: RDRS 56-2011)
• ECO3503 - Harry's Walls, St Mary's, Isles of Scilly - Archaeological Recording (Ref: Report No 2011/07)
• ECO3784 - Isles of Scilly Historic Environment Research Framework

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