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Oliver's Battery, Tresco

A Scheduled Monument in Tresco, Isles of Scilly

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Latitude: 49.9407 / 49°56'26"N

Longitude: -6.3318 / 6°19'54"W

OS Eastings: 89308.396385

OS Northings: 13498.777712

OS Grid: SV893134

Mapcode National: GBR BXRV.2K0

Mapcode Global: VGYBY.6RHB

Entry Name: Oliver's Battery, Tresco

Scheduled Date: 21 May 1963

Last Amended: 25 September 1997

Source: Historic England

Source ID: 1016181

English Heritage Legacy ID: 15504

County: Isles of Scilly

Civil Parish: Tresco

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: Isles of Scilly

Church of England Diocese: Truro


The monument includes an English Civil War gun battery, known as Oliver's
Battery, on the southern headland of Tresco in the Isles of Scilly. Also
included are two platforms accompanying the battery on the headland's east
coast. The battery site also includes evidence for prehistoric activity.
The gun battery is sited on a small rounded hill behind the southernmost tip
of Tresco. Its interior occupies the crown of the hill and measures up to 25m
ENE-WSW by up to 30m NNW-SSE, defined by a subrectangular bank along the crest
of the hillslope, incorporating small outcrops on the south west and south
east; on the north east it meets a massive natural outcrop that dominates the
hill from that side.
The interior has an uneven surface due partly to natural irregularities, with
exposed bedrock behind the southern bank. The lowest, north western, area lies
behind a 3.5m wide entrance gap in the north west corner of the bank. The
higher south eastern corner, directly facing the island of St Mary's, is
occupied by a rounded gun platform, approximately 7m in diameter, giving a
distinct bulge from the line of the battery's south and east banks; the rear
of the gun platform is marked off from the rest of the interior by a slight
bank. In the north east corner of the interior are traces of a small
rectangular building, considered to have been a store or shelter, visible as a
shallow depression 6m long, NNE-SSW, by 3.5m wide in the angle of the
battery's east bank with the massive outcrop to its north.
The battery's earth and rubble bank is approximately 4.5m-8m wide, up to 1.3m
high internally and to 4.5m high externally. From the entrance gap in its
north west corner, a slight approach hollow descends the steep rocky slope to
the north, flanked to its east by two short outer banks extending from the
face of the large outcrop. On the east the steep hillslope drops directly from
the battery bank to the coastal margin. On the south and west the bank is
accompanied by a partly silted flat-bottomed outer ditch, generally 4.5m wide
and 0.6m deep. The outer crest of the ditch meets a narrow flattened surface,
approximately 2m-3m wide, from which the slope descends steeply into a broad
trough encircling the base of the hill on the north, west and south west,
defined along its outer edge by large dune formations. Although this trough is
essentially a natural formation, its line is extended across the hill's lower
slope around the south of the battery by an artificial ditch, generally 5.5m
wide and 1m deep, obstructing approach from that direction.
At the foot of the hill's eastern slope the battery is associated with two
adjacent rectangular platforms, levelled up to 1.5m deep into the lower slope
from the coastal edge. The northern platform measures 16m north-south by 8m
wide, and the southern measures 26m north-south by 12m wide.
The important role played specifically by Oliver's Battery at the end of the
English Civil War is attested in historical records. Between 1648-1651, Scilly
remained in Royalist control. Responding to a threat that the islands might be
occupied by the Dutch, in April 1651 Parliament sent a fleet under Admiral
Blake to recover control and oust the Royalist garrison, whose forces had
built a defensive circuit around the main island, St Mary's. To avoid those
defences, Blake initially attacked and captured Tresco. Over the following
weeks, his troops built Oliver's Battery at the closest point on Tresco to St
Mary's. The guns on the battery bombarded the Garrison, the military focus on
St Mary's, and controlled shipping using St Mary's Pool, its chief anchorage.
Working in conjunction with Blakes ship's, the battery's siege of St Mary's
brought the surrender of Royalist forces on 23 May 1651.
The eroding earth of the battery's southern bank has produced a quantity of
pottery fragments of typical Bronze Age fabric and decoration, indicating
that the battery's construction destroyed part or all of a feature of that
date, considered likely to have been a funerary cairn on this distinctive hill
and broadly contemporary with prehistoric settlement remains exposed on the
shores to both east and west of the headland.
The concrete fabric of the modern metalled road and all modern management
notices are excluded from this scheduling but the ground beneath them is

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.

Source: Historic England

Reasons for Scheduling

The Isles of Scilly, the westernmost of the granite masses of south west
England, contain a remarkable abundance and variety of archaeological remains
from over 4000 years of human activity. The remote physical setting of the
islands, over 40km beyond the mainland in the approaches to the English
Channel, has lent a distinctive character to those remains, producing many
unusual features important for our broader understanding of the social
development of early communities.
Throughout the human occupation there has been a gradual submergence of the
islands' land area, providing a stimulus to change in the environment and its
exploitation. This process has produced evidence for responses to such change
against an independent time-scale, promoting integrated studies of
archaeological, environmental and linguistic aspects of the islands'
The islands' archaeological remains demonstrate clearly the gradually
expanding size and range of contacts of their communities. By the post-
medieval period (from AD 1540), the islands occupied a nationally strategic
location, resulting in an important concentration of defensive works
reflecting the development of fortification methods and technology from the
mid 16th to the 20th centuries. An important and unusual range of post-
medieval monuments also reflects the islands' position as a formidable hazard
for the nation's shipping in the western approaches.
The exceptional preservation of the archaeological remains on the islands has
long been recognised, producing an unusually full and detailed body of
documentation, including several recent surveys.
Civil War fieldworks are earthworks which were raised during military
operations between 1642 and 1651 to provide temporary protection for infantry
or to act as gun emplacements. The earthworks, which may have been reinforced
with revetting or palisades, consist of earth and rubble platforms or banks
and ditches.
The Civil War fieldworks of the Isles of Scilly form a major part of the 150
surviving examples of fieldworks recorded nationally. They present an
unusually complete system of fortifications from this period, both in the
surviving range of fieldwork types represented and in the surviving pattern of
their strategic disposition.
Three main types of Civil War fieldwork have been recognised on the Isles of
Scilly: breastworks, batteries and platforms; these could be deployed
separately or in combination to form a defensive complex.
Breastworks, which on the Isles of Scilly run beside the coastal cliff edge,
consist of an earth and rubble bank, up to 4m wide and nearly 2m high but
generally much smaller, usually accompanied by a ditch on the landward side.
Sixteen surviving examples are recorded on the islands.
Batteries are levelled areas or platforms, generally up to 20m across,
situated on a hilltop or terraced into a slope to serve as gun emplacements.
They vary considerably in size and shape and are usually partially or wholly
enclosed by a bank, occasionally incorporating one or two outer ditches.
Twenty batteries survive on the Isles of Scilly, several connected by
breastworks. Adjacent to some batteries are examples of the third fieldwork
type, platforms. These are partly terraced into, and partly out from, sloping
ground and represent sites of lookouts and temporary buildings. Eight such
platforms, measuring up to 12m by 8m in size, are known to survive on the
islands. These fieldworks and fieldwork complexes were occasionally associated
with other classes of defensive monument on the islands, including earthen
artillery forts and blockhouses.
The fieldworks were designed to defend the deep water approaches to the
islands, especially St Mary's where most examples are found. Fieldworks are
also known from Tresco, Bryher, Samson, St Agnes and Gugh. The circumstances
of their construction are recorded in contemporary historical documents which
indicate most were built by the Royalist forces which controlled the islands
for the entire Civil War period except during 1646-8.

Oliver's Battery survives well, providing a good example of a mid-17th century
campaign battery and one that played a pivotal role in the action to prevent a
Dutch foothold in the Western Approaches and in removing the last stronghold
of Royalist resistance in England at the end of the Civil War. It contains an
unusual range of internal features, while its situation and the extensive
records detailing its function within the overall campaign show well the
strategic methods employed by military forces at this time and the role of
batteries within them.

Source: Historic England


Books and journals
Borlase, W, Observations on Ancient and Present State of the Isles of Scilly, (1756)
O'Neil, BH St J, Ancient Monuments of the Isles of Scilly, (1949)
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993)
Ratcliffe, J, Sharpe, A CAU, Fieldwork in Scilly Autumn 1990, (1991)
Ratcliffe, J, Sharpe, A CAU, Fieldwork in Scilly Autumn 1990, (1991)
Quinnell, H, 'Lighting up the Past in Scilly' in Prehistoric and Roman Pottery, (1991), 73-83
Turk, F A, 'Lighting up the Past in Scilly' in Faunal Remains, (1991), 101-106
Ordnance Survey, Ordnance Survey Record Cards for SV 81 SE 14 & 15, (1978)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7348.01, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR PRN 7347, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR PRN 7348.01, (1988)
Saunders, A D and Young, C J, AM7 scheduling documentation & mapping for SI 589, 1959, With area increased in 1979
Title: 1:2500 Ordnance Survey Map; Cornwall sheet LXXXVII: 2
Source Date:
1888 and 1908 editions
Title: 1:2500 Ordnance Survey Map; SV 8913
Source Date: 1980

Title: Ordnance Survey Record Card for SV 81 SE 14
Source Date: 1978

Title: Ordnance Survey Record Card for SV 81 SE 15
Source Date: 1978

Young, C J, AM 7 & scheduling maplet for extended area of SAM SI 589, 1979,

Source: Historic England

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