Prehistoric field system and post-medieval breastwork and maze on Castella Down, St Agnes


Heritage Category: Scheduled Monument

List Entry Number: 1015697

Date first listed: 04-Oct-1996

Date of most recent amendment: 08-Apr-1997


Ordnance survey map of Prehistoric field system and post-medieval breastwork and maze on Castella Down, St Agnes
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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. Agnes

National Grid Reference: SV 87573 07830


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

Reasons for Designation

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' settlement. 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. Regular field systems are one of several methods of field layout known to have been employed in the Isles of Scilly from the Bronze Age to the Roman period (c.2000 BC - AD 400); closer dating within that period may be provided by the visible relationships of the field boundaries to other classes of monument with a shorter known time-span of use, or by their relationship with an earlier recorded sea level. They comprise a collection of field plots defined by boundaries laid out in a consistent manner, along two dominant axes at approximate right angles to each other. This results in rectilinear fields which may vary in their size and length:width ratio both within and between individual field systems. The fields are bounded by rubble walls or banks, often incorporating edge- or end- set slabs called orthostats. Within its total area, a regular field system may be subdivided into blocks differing in the orientations of their dominant axes. Regular field systems may be associated with broadly contemporary settlement sites such as stone hut circles. Some regular field systems on the Isles of Scilly contain a distinctive association, rarely encountered elsewhere, whereby certain of their field boundaries directly incorporate or link cairns, entrance graves and cists in some groups of prehistoric funerary monuments. Although no precise figure is available, regular field systems form one of the three principal forms of prehistoric field system, along with irregular field systems and some groups of prehistoric linear boundaries, which survive in over 70 areas of the Isles of Scilly. They provide significant insights into the physical and social organisation of past landscapes and they provide evidence for the wider contemporary context within which other nationally important monuments were constructed.

The regular field system on Castella Down survives well, clearly displaying the character of the prehistoric land division and the strong influences upon it of the natural topography. Despite truncation of its lower edges by rising sea levels, the field system contains a sufficient range of elements to determine its nature and extent, assisting our understanding of prehistoric land use over a far wider area than the confines of the monument. In this broader role, the field system complements the other surviving and broadly contemporary settlement remains on St Agnes and Gugh, together with the large cairn cemeteries on Wingletang Down and Gugh, to provide an unusually extensive view of prehistoric land use in this area. The Civil War breastwork in this monument shows well the strategic location where that type of defence was deployed; the surviving pattern of Civil War breastworks and batteries on the Isles of Scilly, of which this breastwork forms an integral part, forms one of the most complete and best preserved defensive systems of that period. Also within the monument the Troy Town Maze preserves its original pattern, confirmed by 19th century photographic evidence, despite some rebuilding. This maze provides a good example of a once-popular and now scarce form of local pastime, and unusually retains the traditional name applied to mazes. Its combination of labyrinthine pattern and mode of construction is unique in England among surviving pre-20th century mazes. It also shows well the significant place that mazes occupy in popular consciousness, not only giving rise to local traditions and place-names but more recently inspiring many copies created in several parts of Scilly by modern visitors.


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


The monument includes a prehistoric field system on the western and southern coastal margins of Castella Down, on the western promontory of St Agnes in the Isles of Scilly. On the south west coast of the Down the monument includes a defensive bank called a breastwork, erected during the English Civil War. Near the breastwork, the monument also includes the post-medieval Troy Town Maze laid out on the coastal slope. The prehistoric field system survives as a series of walls and banks which subdivide the western and southern coastal periphery of Castella Down. Its walling is generally visible as a line of boulders spaced at intervals along the wall course; the boulders are frequently edge-set, commonly 0.3m-0.5m high but occasionally up to 0.8m high. Where present surface vegetation and blown sand deposits permit, the boulders can be seen to rise from slight rubble banks, up to 1.5m wide and 0.3m high, with traces of small facing slabs along each side visible in at least one location. Where their courses roughly follow the contour, the walls become pronounced earthen banks called lynchets, up to 1m high on their downslope side, created by soil movement against and from the boundary due to the early cultivation on the slope. The pattern of walling shows the surviving upper parts of a regular field system, whose surviving plot walls meet at approximate right angles. The dominant axis of the field system is strongly influenced by, and changes with, the aspect of the groundslope, while the actual positioning of several boundaries clearly relates to the incorporation of prominent natural outcrops and large boulders as wall terminals. Reflecting these influences, the western periphery of the Down is subdivided by at least five walls running directly downslope on a north east-south west axis: three form major divisions, 90m-115m apart, extending down from 55m to 70m behind the present coastal edge; the northern and southern each terminate on large outcrops. The other two downslope walls are 40m apart and rise to only 10m-15m from the coastline, forming the sides of a single plot whose south east wall and slightly lynchetted upper bank abut the natural outcrop called the Carns of Castella at the plot's eastern corner. The south east wall of this plot has also been traced as a boulder line across the inter-tidal zone for at least 30m beyond the present coastal edge, reflecting the field system's submergence since the prehistoric period. A further field wall also extends WNW from the inland end of the northernmost major division on the west of the Down, reflecting the change to a north west facing slope and forming a survival of the prehistoric subdivision of that slope whose area is now occupied by post-medieval enclosure. In the west of the Down's southern periphery, two walls run downslope, north west-south east and 20m apart, the eastern only visible at the coastal cliff. Behind the centre and east of the southern periphery, two large adjoining plots are visible. The inland edge of the eastern plot is marked by a high, slightly curving lynchet running WNW from the Pink Carn outcrop; at the west the lynchet meets a wall extending NNE from the Beat Carn outcrop, giving a plot 55m-60m wide with sides defined almost entirely by the rocky scarps of the parallel Pink Carn and Beat Carn outcrops. The wall north of Beat Carn continues 15m beyond its junction with the lynchet to define the east side of the adjoining plot. At the north, the wall turns west across a modern field, defining the inland side of the prehistoric plot. Here its course is visible as the lynchetted line of a recently-removed subdivision of the modern field. The south wall of the adjoining modern field extends beyond this towards a natural outcrop. The west side of the prehistoric plot is considered to correspond with the field wall running SSW as the west side of the modern field almost reaches the coast beside Beat Carn, giving the prehistoric plot a width of 50m-58m. Within the north east corner of the modern field which occupies much of that plot is a small ruined two-roomed building probably of 19th century date. The post-medieval breastwork is visible near the southern end of the Down's western coast. It survives as a slight bank averaging 1.1m wide and 0.15m high, with occasional small slabs projecting through the turf cover. The southern end of the bank commences at the coastal edge, beside the northern end of a group of large massive outcrops marking the south western corner of the Down. From there the bank extends 10m east and then turns north at right-angles, extending for a further 35m, gradually converging on the coastal cliff to the point where the cliff eventually truncates it. In common with the other breastworks erected in Scilly during the Civil War (AD 1642-1651), this bank would give cover for defensive forces along the coast fronting one of the deep water channels into the archipelago, in this case Smith Sound, providing an entry from the south and east which avoided passing close to the heavily defended Garrison promontory on St Mary's. Several metres upslope from the breastwork is a large maze, known as the Troy Town Maze, laid out on the grassy slope within the prehistoric field system. Its paths, worn bare and slightly hollowed by visitors, are defined by single rows of beach cobbles bedded into the surface turf and rising 0.1m-0.2m high. Overall the maze is ovoid, measuring approximately 5.5m north-south by 5m east-west; it has a labyrinthine pattern, with an entrance on the eastern, uphill, side, from which near-concentric curving paths take the visitor alternately from one side to the other, and towards the centre, then to the periphery, and finally back to the centre again. Local tradition maintains that the maze was originally laid out in 1729 by Amor Clarke, a keeper of the St Agnes lighthouse. Although known to have undergone a rebuild on at least one recent occasion, its present pattern matches that clearly shown on an 1885 photograph of the maze. Its `Troy Town' title preserves the name by which mazes were commonly known throughout England in the earlier post-medieval period when they formed a widespread recreational feature; of the few surviving early examples, no other pre-20th century British mazes share the cobble-defined construction of this type of pattern, though the Troy Town Maze itself has inspired many modern copies. The name of this maze has also become transferred to `Troy Town Farm' which occupies much of the promontory within and beyond this monument. Beyond this monument, further prehistoric field system and settlement sites survive from 350m to the ESE and from 750m to the north east on northern Wingletang Down and at Higher Town and Porth Killier respectively; a very large prehistoric cairn cemetery also extends across much of Wingletang Down, and further prehistoric settlement and funerary remains occur widely across the neighbouring island of Gugh to the east. All modern post-and-wire fences, gates and their fittings are excluded from the scheduling but the ground beneath them, and all field walls, are 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: 15453

Legacy System: RSM


Books and journals
Arlott, J, Island Camera, (1983)
Grigson, G, The Scilly Isles, (1977)
Grigson, G, The Scilly Isles, (1977)
Mumford, C, Portrait of the Isles of Scilly, (1970)
Ratcliffe, J, Lighting up the Past in Scilly, (1991)
Title: 1:2500 Ordnance Survey Map; SV 8707 Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:2500 Ordnance Survey Maps; SV 8707 & SV 8708 Source Date: 1980 Author: Publisher: Surveyor:
Title: 1:25000 Ordnance Survey Map; Isles of Scilly: Outdoor Leisure Map 25 Source Date: 1992 Author: Publisher: Surveyor:
Waters, A & Ratcliffe, J/CAU, AM 107 for Scilly SMR entry PRN 7002, (1989)
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7000, (1988)
Waters, A/CAU, AM 107 for Scilly SMR entry PRN 7001, (1988)

End of official listing