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Summary

A fortification erected in 1651-52 when the security of the newly captured islands was threatened by the Dutch fleet.

Protected Status

• Scheduled Monument 15404: CROMWELL'S CASTLE MID-17TH CENTURY BLOCKHOUSE AND 18TH CENTURY GUN PLATFORM ON THE WESTERN COAST OF CASTLE DOWN, TRESCO
• Listed Building (II*) 62549: CROMWELLS CASTLE

Other References/Statuses

• National Monuments Record: SV 81 NE 23
• National Record of the Historic Environment to Historic Environment Records data transfer
• National Record of the Historic Environment: 303385
• OS No. (OS Quarter-sheet and OS No.): SV81NE 23
• Primary Record No. (1985-2009): 7354
• SHINE Candidate (Yes)
• SMR No. (OS Quarter-sheet and SMR No.): SV81NE 1

Monument Type(s):

• ARTILLERY TOWER (Civil War (1642 to 1651) to 17th Century - 1651 AD to 1652 AD)
• COASTAL BATTERY (18th Century - 1740 AD to 1740 AD)

Full description

A 17th century artillery tower, modified in the 18th century, known as Cromwell's Castle, on the east side of New Grimsbury Harbour. The fortification is illustrated and names in the 1889 first edition 6' OS map (1), as well as Spence's map of 1792 (10).

The Castle is discussed by Borlase in 1756 (11), he describes the presence of 9- and 4-pounder guns, and how the fortress was reapired in 1740, but that the timbers were already much decayed due to the lack of garrison. The Castle is also described by Troutbeck in 1796 (12).

O'Neil (2) gives a full description of this fortification erected in 1651-52 and named in honour of Oliver Cromwell. O'Neil says this castle replaced an earlier C16 blockhouse (7354.01) (b2). It was built at a time when the security of the newly captured islands was threatened by the Dutch fleet. An incised date stone re-set on the inside face of the door to the gun platform reads 'M1591H' (6). It replaced King Charles' Castle in the defence of New Grimsby Harbour. The two principle components of the castle were a tall round tower, 13.5m in diameter, built of massive rubble in a style typical of the C16 or C17, and a battery for six guns on the seaward side of the tower. This battery was replaced by Abraham Tovey with a platform in the mid-C18, which carried guns firing over a low parapet (b2). The castle was surveyed and photographed by the OS fieldworker in 1978 (h2). The site was revisited in 1988 (h3) and found to be as described by the IAM and O'Neil. The internal diameter of the tower is 5.85m with walls 2.1m-3.8m thick. Joist holes indicate the original positions of timber floors providing accommodation on two storeys above the basement, with windows and fireplaces. Above the vaulted roof, a stone stairway gives access to the paved gun-platform with six rectangular ports. The lower gun platform on the seaward side of the tower is 9.7m NE-SW by 12.7m NW-SE, paved, with a parapet 0.7m high by 2.1m thick. Small chambers are built against the tower on the lower platform, either side of the present entrance on its SW face. Cromwell's Castle is a Listed Building, Grade II-star (b3). The monument was placed in Guardianship on 11/5/1950 and inclusion in the Schedule was confirmed on 9/10/1981. Scheduling was amended on 1/4/1996 and revised on 24/7/1998.

The site was visited by English Heritage between 2008-10 (4, 5). They suggest that the form of the gun tower with attached platform is characteristically mid-16th century form, but that documentary evidence places construction in 1651-2, and that the dating issue requires resolution. A more general discussion of the castle can be found in the subsequent publication (6). The monument is discussed in a number of general texts and tourist guides (7, 8, 9).

--------------------------------
Site history:
1: 19--. UNKNOWN/IAM
2: 1978. NJA/OS
3: 1988. PARKES, C/CAU
--------------------------------

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

<2> O'Neil, BH St J, 1961, Isles of Scilly MOW Guide, 25, 32-34 (Bibliographic reference). SCO4042.

<3> DOE, Listed Building Description (original DOE), 70 (Bibliographic reference). SCO5173.

<4> Bowden, M, 2011, Isles of Scilly Military Defences, 1540-1951: Earthwork Sites and Minor Features, 6 (Cornwall Event Report). SCO25530.

<5> Field Investigator's Comments, HE/Bowden, M and Brodie, A 2008-10 (Survey). SCO29739.

<6> Bowden, M and Brodie, A, 2011, Defending Scilly (Bibliographic reference). SCO29932.

<7> Pevsner, N & Radcliffe, E, 1970, The Buildings of England: Cornwall, 211 (Bibliographic reference). SCO4128.

<8> ENGLISH HERITAGE, 1998, The English Heritage visitors' handbook, 72 (Booklet). SCO29951.

<9> ENGLISH HERITAGE, 2004, Heritage Unlocked: Guide to free sites in Cornwall and the Isles of Scilly, 64-5 (Booklet). SCO29764.

<10> SPENCE, G, 1792, SURVEY OF THE SCILLY ISLES (Unedited Source). SCO5644.

<11> Borlase, W, 1756, Observations on the Ancient and Present State of the Islands of Scilly, 47ff (Bibliographic reference). SCO2883.

<12> Troutbeck, J, 1796, Survey of the Ancient and Present State of the Scilly Islands, 126 (Bibliographic reference). SCO4965.

Sources / Further Reading

Associated Finds: none recorded

Associated Events

• ECO3819 - Isles of Scilly Military Defences, 1540-1951 (Ref: RDRS 56-2011)

Related records

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