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The Triple Dyke: part of the Iron Age territorial oppidum and Romano-British town of Camulodunum

A Scheduled Monument in Prettygate, Essex

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Latitude: 51.8854 / 51°53'7"N

Longitude: 0.8541 / 0°51'14"E

OS Eastings: 596514.683849

OS Northings: 224612.431165

OS Grid: TL965246

Mapcode National: GBR RLS.LS0

Mapcode Global: VHKFY.RWC0

Entry Name: The Triple Dyke: part of the Iron Age territorial oppidum and Romano-British town of Camulodunum

Scheduled Date: 9 October 1981

Last Amended: 24 April 2002

Source: Historic England

Source ID: 1019993

English Heritage Legacy ID: 29460

County: Essex

Electoral Ward/Division: Prettygate

Built-Up Area: Colchester

Traditional County: Essex

Lieutenancy Area (Ceremonial County): Essex

Church of England Parish: Lexden St Leonard

Church of England Diocese: Chelmsford


The monument includes the visible and buried remains of a section of late Iron
Age or early Romano-British boundary earthwork, known as the Triple Dyke,
located along the eastern side of Straight Road some 3km west of Colchester
town centre.

The section of dyke follows a NNE-SSW alignment (perpetuated by Straight Road)
and extends over a distance of 256m between Chaucer Way and Heath Road. It was
constructed as a series of three parallel banks, each approximately 10m in
width. These have been considerably reduced since the time of construction and
now measure no greater than 1m in height. The banks are separated by ditches
and a further ditch flanks the western side of the western bank. The ditches
are largely infilled, although they can still be detected as slight
intermittent depressions. This section of the Triple Dyke was taken into the
care of the Secretary of State in 1925. It is now the only part of this
type of dyke to remain visible on the ground, and is the only section
included in the scheduling.

The dyke is known to have formerly extended to the north for at least 1.2km,
the alignment having been determined from trial excavations and a series of
aerial photographs taken in the 1930s. The course of the dyke immediately to
the north of the visible section is now overlain by housing. Continuing
northwards, the line is believed to have been interrupted by an entranceway
broadly corresponding to the current position of London Road, before
continuing towards the River Colne at Seven Arches Farm; this northern
extension of the Triple Dyke is not included in the scheduling. In 1961
excavations to the north of London Road in Hunter's Rough (now a housing
estate) found the ditches to be, on average, 6m in width and 2m deep. A
pattern of hobnails, representing a single boot or sandal, was found in the
lower fill of the central ditch.

The Triple Dyke is thought to have terminated to the south near the Heath Road
junction, although a single ditch and bank, possibly the continuation of the
eastern rampart, has been identified over a further 600m (continuing to Dugard
Avenue) through a number of minor excavations. This single dyke (known as the
Shrub End Dyke) is now almost completely overlain by housing and is not
included in the scheduling.

There is currently no definitive evidence for the date of the Triple Dyke,
although its linearity and design is thought to indicate Roman rather than
Iron Age construction. It has been suggested that the Triple Dyke and Shrub
End Dyke were built soon after the invasion of AD 43 to secure a line between
the River Colne and existing dyke to the south of Dugard Avenue (Kidman's
Dyke) and thereby protect the western side of a temporary military encampment
located around the freshwater springs at Lexden. The disparity of design
between the Triple Dyke and Shrub End Dyke to the south is not fully
understood. The process of triplification may have been left unfinished when
the army relocated to the legionary fortress (now beneath Colchester town
centre), or perhaps the length of Triple Dyke simply reflected the maximum
extent of the temporary encampment.

All fences, fence posts and notice boards are excluded from the
scheduling, although the ground beneath these features is included.

The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

The Latin term `oppidum' usually refers to a town, although in the context
of the Roman invasions of Britain, its use in the writings of Julius
Caesar and Suetonius encompassed a wider range of fortified settlements
and native strongholds. In archaeological terminology `territorial oppida'
is used to describe a settlement phenomenon of the later Iron Age - areas
of farmsteads, field systems and nucleated settlements of various kinds
covering wide areas bounded by substantial earthworks. Such sites are
considered to have been tribal capitals or focal places for communities
between the 1st century BC and the 1st century AD, serving as centres of
trade, manufacture and social prominence. Only a handful of sites in
England have been identified under this term (principally Colchester,
Bagendon, Silchester, St Albans, Chichester, Grims Ditch and Stanwick),
all of which lie in southern, central and western parts of the country.
They all share the common characteristic of boundaries defined by massive
linear banks and ditches, sometimes intermittent and positioned to include
natural barriers such as rivers and marshes. The enclosed areas vary from
between 30 sq km and 90 sq km, some marked out by curvilinear boundaries,
others by more rectilinear patterns. Activities within the enclosed areas
may vary considerably and, given that Iron Age society in southern England
was not homogeneous, there is no reason to suppose that all territorial
oppida exhibited the same status or served identical purposes. In addition
to farmsteads, areas of nucleated settlement and related field systems,
other known features of the enclosures include storage pits and wells,
areas set aside for burials (sometimes extremely elaborate), temple
complexes and areas of pottery manufacture, metal working and the minting
of coins. Some, particularly those positioned in coastal or estuarine
locations, provide evidence of widespread trade in the form of imported
goods, notably Gallo-Belgic pottery, from the continental mainland and the
western Roman Empire.
Territorial oppida reflect the development of complex social organisation and
increased permanence of settlement in the late Iron Age. They also provide
some of the most valuable evidence for the impact of Roman conquest and
government on native society. Given the rarity of this settlement form and its
importance for our understanding of the period, all territorial oppida are
viewed as being of national, if not international importance, and all
surviving elements are considered worthy of protection.

The territorial oppidum surrounding Colchester (`Camulodunum' in antiquity)
encompassed an area of about 25 sq km mainly located between the
converging courses of the River Colne and the Roman River to the west of the
Colne estuary. In addition to the rivers the settlement was defined and
protected by the largest group of linear earthworks of the time in Britain.
These developed over a period of about one hundred years from the foundation
of the settlement in the early first century BC and mostly take the form of
large V-shaped ditches with banks constructed from upcast on the sides facing
the settled area. The dykes may have been made still more formidable by the
addition of timber palisades and gateways, and they have been interpreted as
an expression of the settlement's status, as a means to control and protect
grazing stock and as an effective defence against chariots - one of the
principal features of later Iron Age warfare. If placed end to end the dykes
would extend over a total distance of about 25km. Some 6km now survive as
extant earthworks, and many other sections are known to survive as buried

The interior of the oppidum is thought to have been largely agricultural - a
mixture of enclosed fields, pasture and woodland - with small occupation sites
scattered throughout and two particularly large and complex areas of activity
located to the west and to the north. At Gosbecks, to the west, an extensive
farmstead has been identified. This has been associated with Cunobelin (one of
the most famous British kings prior to the Roman Conquest) and interpreted as
a centre of political authority and religious practice. Further north, at
Sheepen, excavations in the 1930s and 1970 revealed widespread evidence of
industrial processes, the minting of coins and continental trade. Associated
with the settlement sites are burial grounds, the most prominent of which are
the Lexden Tumulus, Lexden Mount, a group of excavated burial enclosures at
Stanway (beyond the western dykes), and a similar (unexcavated) enclosure at
Gosbecks. These sites reflect the beliefs and complex burial rituals afforded
to the society's elite; a large number of less elaborate burials have been
discovered across the oppidum.

The rulers and occupants may have fluctuated according to the relative
fortunes of two rival tribal polities - the Trinovantes centred on modern
Essex and the Catuvellauni based in modern Hertfordshire. An alternative
suggestion is that the oppidum served as a Catuvellaunian colony within
Trinovantian territory, maintained through political agreements or the warlike
ascendancy of the former in order to provide this otherwise landlocked tribe
with access to coastal trade. In either case, the oppidum was clearly of
central importance to the region in AD 43 when it formed the primary military
objective for the invading Roman army. After the collapse of local resistance
the Emperor Claudius personally led his victorious forces into the oppidum -
which was subsequently reorganised to provide a centre of provincial
government and bridgehead for the further conquest of Britain. A small Roman
fort was constructed within the Gosbecks complex, and a larger legionary
fortress was established on the hill to the east (now the centre of modern
Colchester). As the focus of military activity shifted towards the north and
west of Britain the fortress was redesignated as a `colonia', a chartered town
for a colony of retired soldiers. `Colonia Victricensis' (City of Victory) was
the first Roman town established in Britain and thus the earliest truly urban
settlement in the country. The burgeoning town was destroyed in AD 60-61 - the
first major casualty of the tribal revolt led by Boudicca, queen of the Iceni.
In the aftermath of the revolt, the town was rebuilt with a protective wall
(based on the perimeter of the earlier fortress), and with the return of order
the colonia developed in a manner apparently calculated to integrate the old
and new social orders. Native settlement and burial practices continued within
the territorial oppidum (now probably a `civitas' or self governing town)
which was protected with additional dykes. A temple and a theatre were
constructed at the Gosbecks site, and the Sheepen industrial zone was
maintained, enlarged and extended to include a further religious complex.

The collapse of Roman government in the early fifth century signalled the end
of Colonia Victricensis. Medieval Colchester emerged within the walls of the
former Roman town leaving the greater part of the extended settlement and
oppidum to disappear beneath its rural hinterland. As a consequence the
archaeological remains in this area are remarkable for the lack of later
disturbance and present a unique opportunity for the study of the Iron Age and
Roman past.

The Triple Dyke is one of the best surviving examples amongst the linear
earthworks which defined the perimeter of the Iron Age and Roman settlement.
The banks will contain valuable archaeological evidence for the date and
manner of their construction, and the buried ditches will similarly contain
valuable evidence for the date when this section was built and the period over
which it was maintained. The buried silts within the ditches may contain
environmental evidence illustrating the appearance of the landscape in which
the dyke was set, and the buried landsurface beneath the banks may retain
sealed evidence of earlier occupation in the area.

The Triple Dyke, together with its continuation to the south (Shrub End
Dyke), is thought to be a Roman construction. The majority of dykes within
the system which surrounded Camulodunum were designed to defend the late
Iron Age oppidum and its Romano-British successor. The Triple Dyke,
however, appears to be a unique variation - built specifically to
consolidate the position of the invading forces at an early stage in the
Claudian invasion. As such it provides a valuable insight into the
military campaign aimed at the conquest of Camulodunum.

Source: Historic England


Books and journals
Hawkes, C F C, Crummy, P, 'Colchester Archaeological Reports' in Camulodunum II, (1995)
Hawkes, C F C, Crummy, P, 'Colchester Archaeological Reports' in Camulodunum II, (1995), 174-77
Deed of Guardianship (File AA 40545), Lexden Straight Road, (1923)
Radford, D and Gascoigne, A, The Colchester Iron Age Dykes: Archaeological summary, 1997, Colchester Museums Internal Report

Source: Historic England

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