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Prehistoric field system and cairn, early and later medieval religious complex, post-medieval lookout and quarantine station on St Helen's

A Scheduled Monument in Tresco, Isles of Scilly

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Latitude: 49.9711 / 49°58'15"N

Longitude: -6.3265 / 6°19'35"W

OS Eastings: 89884.5197

OS Northings: 16856.3157

OS Grid: SV898168

Mapcode National: GBR BXRR.QYS

Mapcode Global: VGYBR.9Z9J

Entry Name: Prehistoric field system and cairn, early and later medieval religious complex, post-medieval lookout and quarantine station on St Helen's

Scheduled Date: 25 September 1997

Source: Historic England

Source ID: 1016177

English Heritage Legacy ID: 15498

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 scheduling includes a prehistoric field system on the southern flanks and
summit of St Helen's, a small island in the north of the Isles of Scilly. It
also includes a prehistoric funerary cairn with remains of a chamber and post
medieval lookout on the summit of the island's hill, and, on the south slope,
an early and later medieval religious complex. Behind the south coast, the
monument contains a mid-18th century quarantine station.
The prehistoric field system encompasses much of the island's southern flanks
to roughly the 15m contour level but rising close to the island's summit on
the east. It varies greatly in boundary form and layout. On the west it is
defined by low banks with spaced edge-set slabs called orthostats,
approximately 0.5m high. Some banks along the contour are backed by
accumulated deposits, called lynchets, due to early cultivation on the slope.
Much of the western flank is divided into a rectilinear grid of small plots by
north east-south west downslope banks approximately 15m-20m apart, crossed by
north west-south east banks at approximately 20m-25m intervals. To the south,
the grid pattern meets a block of small rounded plots, approximately 10m-20m
across, reflecting a differing phase of layout. The field system also extends
east over the island's south and south east slopes as a series of lynchetted
banks approximately 0.5m-1.5m high along the slope. The south slope lynchets
again extend to roughly the 15m contour. Those on the south east slope are
slighter, with some downslope banks immediately behind the coast, but they
also extend onto the gentler upper slope where the lynchets revert to banks
with spaced orthostats, similar to the west flank boundaries: one bank
ascends the slope's northern upper ridge to join a rectangular plot that
crosses the head of the slope to end near the summit. A further bank to the
north west extends along part of the slope crest above the island's north east
On the summit is a prehistoric cairn with an ovoid mound, to 17m across, and a
shallow-domed surface up to 1.5m high. West of centre, its funerary chamber
survives as a slab-lined rectangular hollow, 0.8m north east-south west by
0.7m wide, open to the north east and partly covered by a slab 1.2m long. On
the mound's east side is the lower walling of a post medieval lookout,
rectangular in plan and 3m wide north east-south west by at least 3.2m long
internally, open to the north west, with an Ordnance Survey triangulation
point overlying its south west wall.
The early Christian complex on the island's lower southern slope was, by
early tradition, founded by St Elidius. Its initial phase, datable to the
8th century AD, includes a sub-rectangular embanked enclosure, approximately
46m ENE-WSW by approximately 35m NNW-SSE internally, containing three early
features: a chapel at the north east, a living cell on the west and a
The chapel is 3.5m east-west by 2.5m wide internally, with walling to 1.6m
high and an entrance at the centre of the south wall. A step defines the
eastern sanctuary with a small rubble altar block, 0.7m high, with end-set
slabs at each side and a niche for holy relics at the south. A rubble seat
links the altar with the north wall. A low slab-edged bench, probably added
later, runs within the chapel wall beyond the sanctuary.
The round living cell is 3.75m across internally, defined by a rubble wall to
1.5m high; the original entrance is on the WSW with a later entrance on the
ENE. By the ENE entrance is an oval hearth slab edged by low slabs. Excavation
revealed five graves of an early cemetery east of the living cell.
In the early 11th century a small church, 7.9m east-west by 4.25m wide, was
built north east of the living cell. Around 1120, Tavistock Abbey was granted
the church and increased exploitation as a place of pilgrimage to the saint's
shrine led to extensive remodelling, extending the church eastward to give a
new sanctuary; a north aisle with a paved sanctuary was also added. The nave
and aisle walls survive approximately 1m-1.5m high with remains of rubble
benches inside.
On a sketch of 1752, an arcade of two round arches on squat pillars linked the
north aisle with the nave. Excavations found decorated ridge-tiles and part of
a 12th century Purbeck marble shrine to house the saint's relics. The church
was in disrepair by the mid-15th century and probably in ruins by the
dissolution of Tavistock Abbey in 1539 but memory of reverence of the saint's
shrine survived to be recorded by the antiquary Leland in 1542.
The remodelling also reduced the enclosure area almost by half by a wall from
its north bank to shortly beyond the living cell, where it meets an approach
passage and turns east to join the east bank. The living cell entrance was
altered to face ENE into the reduced enclosure. Three small rectangular living
cells are later additions on the south and east of the enclosure.
A quarantine station was established on St Helen's in 1764 after an Act ten
years earlier required any plague-ridden ship north of Cape Finisterre and
heading for England to anchor in St Helen's Pool, south of the island. The
station includes an isolation hospital, well, slipway and field system. The
isolation hospital, known as the `Pest House', is at the foot of the island's
southern rocky spur and is a roofless single storey building with rubble walls
faced externally by neat coursed slabs called ashlar; traces of plaster
survive inside. It has a main room, 4.9m square internally, and an extension
with a lean-to roof on the south east, later subdivided into two rooms. On a
late-19th century photograph the main room has a pyramidal roof and the
extension a sloping roof with a door and two-light window in its north east
room. The water supply came from a well 50m to the west.
Landing on St Helen's was facilitated by a slipway south west of the Pest
House, visible as a straight NNW-SSE sandy channel approximately 10m wide,
cleared across the boulder shore. On each side is a breakwater of contiguous
slabs, some coursed, extending at least 41m along the west side and 20m along
the east.
A small field system associated with the quarantine station lies immediately
behind the south coast, walled by rubble-faced banks. Three fields adjoin in a
north east-south west line; the largest, at the south west, is subdivided into
at least four smaller plots. A burial found eroding from a coastal dune over
the field system's south corner contained the skeleton of a negroid or
oriental male, considered to be a late 18th-early 19th century burial of a
shipwreck victim.
All modern notices and signs are excluded from the scheduling but the ground
beneath them is included.

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.

Each phase of prehistoric, medieval and post-medieval activity on southern St
Helen's has produced remains which survive well, presenting a highly unusual
succession of land uses. The prehistoric field system shows clearly its varied
manner of construction and layout, containing evidence for multi-phase
development and demonstrating the strong influence of the nature and aspect of
the underlying landforms. The importance of the local topography is also
illustrated by the siting of the summit cairn, which survives substantially
intact despite some evident disturbance for the construction of the post
medieval lookout and OS trig point. These prehistoric features are important
for understanding the nature of early land use in the north of Scilly and can
be set in their wider pre-submergence context by the survival of broadly
contemporary settlement and funerary features on nearby islands. The early
Christian complex in this scheduling is a very rare survival, in barely
modified form, of an early medieval religious enclosure complete with its
cemetery, chapel and living cell. It is extremely valuable for studies of the
early development of Christianity in western Britain, similar to early
enclosures called `lanns' identified as the original forms that developed into
many present parish churchyard sites in south west England and resembling a
small number which survive intact in Ireland. The St Helen's complex is of
particular value as one of at least three early medieval Christian foci to
survive on Scilly, each containing a chapel but with differing accompanying
features: a rare grouping in a small area which illustrates the diversity of
religious sites in this period, their relationships to each other and to the
wider settlement regime containing them. The later modifications give a good
example of a developing site of pilgrimage during the medieval period, and the
evolving plan of a small church. The quarantine station on the south of St
Helen's had a national role as an attempt to safeguard the country from
shipborne infectious diseases arriving via the Western Approaches; it is a
well preserved and unusual illustration of the mid-18th century measures to
control and improve public health.

Source: Historic England


Books and journals
Arlott, J, Island Camera, (1983)
Grigson, G, The Scilly Isles, (1977)
IoS Council members, , One Hundred Years of the Council of the Isles of Scilly, (1991)
Ratcliffe, J, Fieldwork in Scilly July 1993, (1994), 23-49
Ratcliffe, J, Fieldwork in Scilly July 1993, (1994), 23-49
Ratcliffe, J, Scilly's Archaeological Heritage, (1992)
Ratcliffe, J, Fieldwork in Scilly July 1993, (1994), 23-49
Ratcliffe, J, Fieldwork in Scilly 1991 and 1992, (1993), 27-31
Ratcliffe, J, Fieldwork in Scilly July 1993, (1994)
Ratcliffe, J, Sharpe, A CAU, Fieldwork in Scilly Autumn 1990, (1991)
Tangye, M, A Guide to The Old Church of St Mary The Virgin, Isles of Scilly, (1995)
Thomas, C, Exploration of a Drowned Landscape, (1986)
Thomas, C, Exploration of a Drowned Landscape, (1986)
Thomas, C, Exploration of a Drowned Landscape, (1986)
Bluett, A, 'The Cornish Magazine' in Around the Manacles, , Vol. I, (1898), 403-416
O'Neil, H E, 'Archaeological Journal' in Excavation of a Celtic Hermitage on St Helen's, Scilly, 1956-58, (1964)
O'Neil, H E, 'Archaeological Journal' in Excavation of a Celtic Hermitage on St Helen's, Scilly, 1956-58, (1964), 40-69
Hooley, AD, Note on discovery & removal of burial on St Helen's, 5-6/4/1995, 1995, Unpubl report for EH and CAU records
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7114.01, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7114.02, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7115 & 7115.03, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7268.02, (1988)
Parkes, C/CAU, AM 107 for Scilly SMR entry PRN 7268.03, (1988)
Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7112 & 7113, (1988)
Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7115 & 7115.04-.05, (1988)
Parkes, C/CAU, AM 107s for Scilly SMR entries PRN 7268.01-.03, (1988)
Title: 1:10000 Ordnance Survey Maps: SV 81 NE & SV 91 NW
Source Date: 1980

Title: 1:2500 Ordnance Survey Map; Cornwall sheet LXXXII: 10
Source Date: 1906

Title: 1:2500 Ordnance Survey Map; Cornwall sheet LXXXII: 16
Source Date: 1889

Title: 1:2500 Ordnance Survey Map; Cornwall sheet LXXXII: 16
Source Date: 1889

Title: Ordnance Survey Record & Illustration Cards for SV 91 NW 55
Source Date: 1978

Unpubl report for EH and CAU records, Hooley, A D, Archaeological note on burial at SV 90121682 on SE St Helen's, (1995)

Source: Historic England

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