is a history graduate and freelance writer with a
passion for Early Medieval history. He has
visited countless Dark Age sites across the
country dragging his poor family behind him! His
biggest claim to fame was his discovery of the
skull of an Iron Age bog body near Lincoln in
2003. Read more of his Dark Ages' articles on his website.
Vortigern Studies Index
.Wansdyke Project 21
is part of
Dark Age Dykes
across Britain there are earthworks that are thought to
have been built in the Dark Ages which have rarely been
analysed, which is rather odd as early Medieval Britons
are archaeologically often invisible. With many
historians shying away from the term Dark
Ages because of its negative connotations I wonder
if the period may be more accurately be named the
Dyke Ages as so large and impressive are
these structures. Some, however, may not all date to this
period as the lack of documents from this time period
makes it very easy to ascribe any mysterious boundary to
this time especially as linear boundaries are difficult
to date through archaeology as domestic rubbish, burials
and building foundations which usually provide good
buried dating evidence are rarely found associated with
them. They are a widespread phenomena in Britain and as
such they are worthy of closer scrutiny as they may be
able to tell us more about the politics, economics,
methods of war, culture and population levels of Dark Age
societies. No historian has ever given an extensive list
of these moments (though scraps of pottery or the odd
coin can stimulate reams of speculation) so I give a
brief gazetteer below. I do not believe the list is
exhaustive or the accompanying descriptions completely
error free so please do not hesitate to contact with any
fresh insights about these mysterious barriers. With some
of the dykes the only information I have has been taken
from old or extremely basic local guide books so the
information I have is very patchy (in an ideal world I
wouldnt have even started this article without
another six months full time study!)
Norfolk has a series of Dark Age dykes: Fossditch,
Bichanditch, Launditch, Panworth
Ditch and the Devils at Garboldisham.
Launditch and Panworth both face westward and cut Roman
roads (therefore they must post-date 407AD). Peter
Wade-Martins thought they were built by the Britons
against the Anglo-Saxons in the Wash area and the dykes
were patrolled by cavalry. He claims Fossditch and Bichanditch were
built by the Anglo-Saxons as they face east and adjoin
fenland where the Anglo-Saxons could have first landed
(early ham places names seem to be concentrated
behind the ditches). Bichanditch, however, does face
Swaffham which was an early Anglo-Saxon site. Dymond
postulates that Bichanditch was built to defend Britons
against Germanic, and specifically Swabian, settlers in
The Roman town of Silchester is surrounded by a series of
earthworks, but some of these are Iron Age in date built
to protect the pre-Roman settlement. Some of the dykes do
cut Roman roads leading to the town from the Thames
Valley (where there is evidence of early Saxon
settlement). The city should be bisected by the northern
border of Hampshire, but the border bulges out in a
semi-circular salient following the dykes. This salient
is made up of the two parishes of Silchester and Mortimer
West End which form a circular piece of territory 3 miles
in diameter centred on the city and may be a Roman urban
district boundary that has influenced the layout of Saxon
Just to the east of Housesteads fort on Hadrians
Wall is a north-south earthwork with a ditch on the
western side called Black Dyke which is
traditionally thought to be the border between the
English kingdom of Bernicia and the British kingdom of
Rheged. On older maps it runs from northern Northumbria
to Allenheads in Durham, but now it just runs from the
North Tyne at Tarset to Moraleeon the South Tyne.
Between Galashields in the Borders and Peel Fell is a
dyke called the Cattrail, which is 45 miles
long, 26 feet wide and with a bank on each side at least
ten feet high. As it divides the coastal area from
inlands parts it may have been built by the Britons
against the English kingdom of Bernicia.
Grey Ditch in the Peak District is a mile long
bank with a ditch on the south side. The area to the
north of the ditch seems to show signs of British
survival and the area to the south signs of early English
settlement so it has been seen as a British built.
Barnatt and Smith say of Grey Ditch: This large
linear bank and ditch cuts right across the main valley
which provides a route between the Hope valley and the
fertile areas of the plateau to the south. There are two
other short linear ditches in the region which could also
been seen as separating Anglian and British
communities. Map reference SK 173/818 to SK 184/813.
Cornwall has two dykes that are considered to date from
this period: Bolster Bank at St Agnes (which is
visible between Trevaunance Cove and Chapel Coombe) and
the six mile long Giants Hedge between
Lerryn and West Looe (best seen north of Lanreath). The
Map reference for the Giants Hedge is SX 245/535 to
SX 150/569. Both have been interpreted as Cornish
defences against the incursions of Wessex.
There are two distinct dyke groups that have
traditionally been seen as defences put up to save this
British kingdom from English attack. Grims
Ditch runs for five and a half miles north-south
from near Willington to Whinmoor. It faces east and
protects the Leeds area from attack from the Humber area.
The bank is still in places eight feet high and the ditch
30-40 feet wide, though housing developments have
destroyed much of the northern part. The other set of
dykes are called the four and a half mile long Aberford
Dykes and they are a varied group of three distinct
dykes: The Ridge (also called Becca Banks),
South Dyke and The Rein. The Ridge is
three miles long, faces south (towards where Elmet
traditionally would be) and runs from Barwick to east of
Aberford. The Ridge is still 25 feet from the bottom of
the ditch to the top of the bank. The Rein also faces
south and is a mile long, but is probably an Iron Age
boundary. The South Dyke is 1000 yards long and faces
north facing the direction of York.
I have read that this part of Scotland was a Pictish
enclave surrounded by the British kingdoms of Rheged and
Strathclyde that built a long linear earthwork to protect
itself. The idea of a southern Pictish kingdom in
Galloway sounds a little dubious to me, but may help
explain how the Picts raided the west coast and how St
Ninian converted Picts from Withorn.
Cambridgeshire has four very impressive dykes: Brant
Ditch, Brent Ditch (which faces to the
north-east whereas the others all face south-west), Fleam
Ditch (which means fugitives ditch) and the
huge Devils Ditch (the inner ditch if this
is a system of ditches built at the same time).
Excavations in the 1970s failed to provide any dating
material, but did show the ditch was built by a series of
gangs (the construction was not uniform along the length
of the ditches) and while the ditch at Devils Ditch
was never cleaned out after construction, Fleam Ditch was
regularly cleared. Devils Ditch is seven miles long
and cuts off East Anglia from Cambridgeshire. There have
been many explanations as to who built them such as the
kings of East Anglia built them to prevent attacks from
the Britons in the 6th century or against
attacks from Mercia in the 6th/7th
Centuries. They are mentioned in the Anglo-Saxon
Chronicle in 905 when it is said King Edward harried the
Vikings between the Dykes and the River Wissey (Ouse?) so
they must pre-date the 10th Century. Bran is
three miles long, Brent under two, Fleam in two sections
about six miles in total and Devils is about 6
Between Reeth and Grinton in the Yorkshire Dales are a
series of dykes that have been traditionally been seen as
defences set up in 70 AD against the advancing Romans,
but could easily been erected by the rulers of Rheged
against the Northumbrians.
Bassett argued that the nearby linear boundaries
are Dark Age and demarking a sub-Roman enclave based on
the town deep in the territory of the East Saxons.
Dark mentions a Clawdd Mawr in Dyfed. There are
four other possible Dark Age Welsh dykes: Clawdd Mawr
(near Penybontfawr/Llanwddyn in Powys), Crugyn Bank
(a one and a half mile long dyke to the south of Dolfor,
Powys), Short Ditch (near Knucklas, Powys) and Giants
Grave, a dyke about 250 metres long south east of
Llandinam which has had deposits underneath it carbon
dated to 340-530 AD (there is a short report in
Archeaology of Wales Vol. 43, p77). The Clywd-Powys
Archeaological Trust is investigating the last four short
dykes and their report is due in March 2006.
Dorset has three north facing linear earthworks that seem
to be designed to protect the Britons in the area from
the expanding kingdom of Wessex. The most northerly is
called Bokerley Dyke which was partially built
on top of a series of earlier earthworks called Grims
Ditch (which were probably Iron Age field boundaries
built to divide large cattle grazing areas). Bokerley
still defines the Dorset-Hampshire border and seems to
protect the Romano-British settlement at Woodyates
against attack from Hampshire. Coins from the reign of
Valens (364-78) and Honorius (393) found during
excavations of the dyke suggest it may date to the early
5th century. It is over three miles long and
when I last visited it was in many places taller than
myself (that is about 6 feet or more) so it was more than
a mere hedgerow, but Bowen and Dark thought that it was a minor
boundary. Dark describes it as a: heightened,
earlier boundary bank of potentially, only local
significance. Map reference SU 025/2000 to SU 063/168.
middle ditch in Dorset is called Combs Ditch and
is situated just to the south-west of Blandford Forum. In
parts it is 9 feet from the top of the bank to the bottom
of the ditch. At present it is about 2 miles long and
like Bokerley the ditch is the north of the bank. Map
reference ST 853/022 to SY 887/995 (the southern end is
indistinct and that last reference may be wrong).
The final linear Barrier in Dorset is Battery Banks
which runs west of Wareham along a ridge between the
rivers Frome and Piddle to cut off the Isle of Purbeck
from the north. There is also a cross ditch to prevent
invaders attacking along the ridge. It is over four miles
in length from the western most part to the most easterly
part, though it cannot be traced at all points in
imagine these defensive lines being patrolled by a small
group of cavalry based in settlements nearby (Woodyates
for Bokerley, possibly Winterborne Whitchurch for Combs
and Wareham for Battery Banks). These garrisons need only
be a dozen strong as all three lines are quite short and
have great views for miles to the north. The patrols
could sound the alarm using horns, fires or an errand
rider and hold the defences until the local militia
turned up. Due to the superb views to the north at
Bokerley the settlement of Woodyates is closer to the
defences than the raiders would be when they came in
sight of a horseman standing on the dyke so the local
farmers would have time to grab their spears and get to
the dyke before the enemy could. Perhaps it was such
garrison that provided the stimulus for the growth of
Wareham (popular opinion supposes Wareham to be Roman,
but no substantial Roman finds have ever been unearthed
there). Employing full time mounted troops would have
been a strain on the local rulers, but if it meant that
cattle were not stolen and crops burnt could have made it
very economic (I bet the raiders would have soon turned
their attentions elsewhere), though it would have taken a
major organisation of resources to build them in the
first place. Map reference SY857/886 to SY 911/874.
Wansdyke is one of the most famous Dark Age dykes, but it
is in fact two earthworks (the piece that used to be
believed connected the two pieces is now known to be a
Roman road). The western half extends nine miles from
Dundry Hill south east of Bristol to just south of Bath.
The eastern half runs ten miles from south of Calne to
Great Bedwyn on the edge of Savernake Forest. Both halves
could have been built by the Britons, perhaps originally
by Ambrosius, against the Saxons of the Thames Valley.
The enigmatic Battle of Fethanleag or Battle Wood between
the West Saxons and the Britons recorded in the
Anglo-Saxon Chronicle could report a British victory in a
campaign along this border as the Saxon king turned back
to his territory in anger. Alternatively
either could have been built by the kings of Wessex
against the might of Mercia, perhaps around 628 when a
battle is recorded against the Mercians at Cirencester.
The former is more likely as the name of the dyke builder
was forgotten and it was named after the Germanic god
Woden when the Saxons of the area still named things
after pagan gods and Wessex was converted to Christianity
in 628. Its existence is implied by a charter dated to
941 when a hillfort adjoining the dyke which is now
called Stantonbury Hillfort is named Merces Burh or
border fort. Ian Burrow looked at two hillforts along the
western part of the dyke that have been incorporated into
its structure (Stantonbury and Maes Knoll) and concluded
that the builders used the hillforts to save on labour,
but did not refortify the forts, garisson them or patrol
the dyke as a walkway through the ramparts was not built.
He concluded: that the dykes were simply an
emphatic expression of territoriality..
DYKE (CLAWDD OFFA) AND WATS DYKE:
This famous linear earthwork marks the Welsh border and
as the bank is on the east and the ditch on the west it
was built against the Welsh, probably by the Mercian King
Offa (who ruled 757 to 796). It was Asser, King
Alfreds friend and biographer, in the ninth century
who first ascribed the dyke to Offa. Offas Dyke is
newer (so we think we know who built it and when), it has
been more heavily studied than most other dykes and is
larger so more of it survives so we know more about it
than other linear boundaries. Sir Cyril Fox carried out many surveys on the dyke in
the 1920s and said it ran 149 miles from sea to sea,
though only 80 miles were built (the gaps being covered
with thick forest on the heavy clay soil). In parts the
bank is still 8 feet or 2.5 metres high. A recent book claims it was built by the Emperor
Septimus Severus about 200AD, but this is probably not
correct as Roman deposits have been found sealed under
the dyke (at Ffrith) and the sources of the story of
Severus building a turf wall in Britain are probably
confused references to him rebuilding the Antonine Wall.
Bede, who realised that Gildas date for the
Antonine Wall was too late, found a reference in the life
of Severus by Aelius Spartianus. This described Severus
building a wall across the island from sea to sea and,
presuming the turf wall was the older, Bede assumed this
referred to Hadrian's Wall. Aelius Spartianus also wrote
a biography of Hadrian which Bede obviously did not read
or if he did he didnt believe (these two
biographies are part of the Augustan History that
historians now believe is all the work of the same person
so Aelius Spartianus may be a pseudonym).
Severus fought against the Picts and would have
refurbished the Antonine Wall and would have no reason
for building a barrier in the middle of the Roman
province of Britain.
guide written by two historians who have spent decades
surveying and digging the monument claims that the dyke is only 64 miles
long from Rushock Hill (SO 300/595) north to Treuddyn (SJ
268/577) and lots of the parts marked by Fox do not exist
and dismiss the idea that there was heavy forest on the
clay soils that mark the gaps (the Domesday
Book shows Herefordshire as comparatively unwooded). Fox
was confused with other smaller dykes (Whitford Dyke,
Rowe Ditch, Lyonshall Bank and Scutchditch
among others) that could date from prehistory to Tudor
times and Wats Dyke in the north. Hill and
Worthington argue quite convincingly that it was not a
border between the English and the Welsh, but a border
between Mercia and Powys (which would explain the
northern and southern gaps as they cover the borders of
Gwynedd and Gwent). We know from the Pillar of Eliseg
that a Powys king who was contemporary to Offa was taking
land from the English. It was used to be thought that the
dyke was purely symbolic with large gaps in it to allow
trade with the Welsh, but many suspected gate sites have
been dug and no gaps in the ditch have ever been found.
Hill and Worthington say the dyke was built by different
gangs (as in Cambridgeshire) and probably patrolled
(which would take 300 foot soldiers or fewer on
horseback), but not garrisoned. They postulate a system
of fortified villages (there are lots of place names of
villages near the rear of the dyke that suggest they were
enclosed and may be militia muster points) linked by
beacons though a reviewer on the Clywd-Powys
Archaeological Trust website say they have rather
stretched the evidence.
Burghal Hideage, an Anglo-Saxon document that dates to
about 900AD, implies that one man is needed to maintain
(or possibly build) just over 4 foot of defences (1.26
metres) so it would have taken about 75,000 men to build
it or fewer if built over a number of years. A man could
no doubt construct more than 4 ft of defences in a year,
but this calculation is probably based on what a man can
do in his spare time who is engaged in agriculture full
Tribal Hideage, an eighth century document, says the
north Mercians had 7,000 households and the south
Mercians 5,000, so Offa must have conscripted labour from
the other tribes that made up Mercia as well as kingdoms
that accepted his overlordship.
Dyke was thought to have been just over 20 miles long,
but is now thought to run 38.6 miles from Lower Morton
(SJ 305/233) to Basingwerk (SJ 195/775) and incorporates
the hillfort at Oswestry. Fox dated it to the reign of
Aethelbald (716-57), but a recent radiocarbon date
suggests the late fifth or early sixth century, so
perhaps it was built against the kingdom of Gwynedd under
the powerful king Maelgwn.
is one of the few historians to discuss these vast
monuments and says they show the power of Dark Age
British kings to conscript labour, especially in the
Somerset area. He suggested the labour may have been
organised using service renders in lieu of money taxation
which had ended when the widespread use of coinage ended
in the early 5th century in much the same way
that the Romans organised the Britons to work on the
maintenance of Hadrians Wall in the late Roman
period. He also obliquely suggests the West Country dykes
may have been used by the local royal families to control
construction of the dykes does show there was a vast
amount of labour available (which goes against the theory
of a mass depopulation in the immediate aftermath of the
fall of Roman Britain as expounded by historians like
Dark). There are at least 240 miles (or 385 km) of dykes
in Britain that probably date to the Dark Ages and if the
Burghal Hideage is correct to think that a man could be
expected to construct 4 foot and one and a quarter inches
of fortifications in a year that is nearly a third of a
million people needed to maintain and construct them (if
they are each built in a single year). This shows borders
were stable long enough both to be worth delimiting and
to allow the labour to be conscripted, organised and the
dyke built. There seems to have been conflict (anything
from mass invasion to cattle rustling) or the fear of
conflict among many societies so the belief that the Dark
Ages were peaceful seems to be false. Both Anglo-Saxon
and British monarchs seem to have built dykes so both
cultures were copying tactics off each other and off the
Romans (who famously built linear fortifications). They
are named after the Devil, giants and pagan gods so
obviously the proponents of the continuity school of Dark
Age history need to explain how the undisturbed local
peasantry who obviously had to build the things so
quickly forgot who had ordered the building these vast
of these dykes have been categorised in the past as the
border between Celtic/British kingdom A on one side and
Anglo-Saxon kingdom B on the other, but this may be
overly simplistic. Many of these dykes could have been
built between kingdoms where the monarchs on both sides
thought of themselves as English or they could be older
than we think and they could be borders between British
kingdoms. Even if the king on one side spoke English and
worshiped Woden that does not necessarily mean that all
his subjects had ancestors from northern Germany. These
dykes do influence cultural patterns as the earliest mass
produced Anglian pottery (Illington-Lackford pottery)
does seem to have a distribution pattern: bounded
by three early medieval linear earthworks. These dykes may, however, have hardened
cultural divides in Britain and may be one of the reasons
that the English language adopted so few words from the
older British language. Two genetic studies both show that even today genetic
signatures differ between central England and Wales and
we know the nations either side of Offas and
Wats dykes show linguistic and cultural differences
even today despite the fact that the border has not been
a political one for about 700 years.
from Offas Dyke and possibly some of the
Cambridgeshire dykes there is a good case for assigning
most of the as being of British construction. Perhaps
this tendency for the native Britons to adopt defensive
tactics against an aggressive invader is why the Britons
could never defeat the initially far fewer invading
Anglo-Saxons and why the Anglo-Saxon invasion stopped at
the Welsh border when the English adopted these defensive
these dykes worked as military structures (or even if
they were military structures) is open to debate. Some
may have been garrisoned and patrolled, but others seem
not to have been so to generalise may be dangerous. Some
could have been purely symbolic borders or places where
the movement of goods was controlled (like the Salt Tax
Hedge in India, a purely economic border between two
areas both under British control showing a barrier does
not have to be a political border). They seem to have
been based on military fortifications and so at the very
least were used to deter invaders, perhaps being designed
to slow down small, mobile raiding parties to stop them
carrying off goods or cattle across open country (most of
the dykes stop at heavy woodland or marshy valleys).
rash of dyke building may have been initially inspired by
Hadrians Wall (Gildas dates its construction far
too late, perhaps being confused by stories of a final
refurbishment of the wall in late Roman times or possibly
being confused by stories of dyke building by the Britons
after the end of Roman Britain) or by the rash of
hill-fort refurbishment that went on in this period. They
need further study: excavations to look for dating
evidence, surveys to find out how many man hours were
needed to build them and serious research into the
origins of their names. Perhaps these enigmatic
structures could tell us so much more about this crucial
period of British history.
 Wade-Martins, P. (1974): The Linear
Earthworks of West Norfolk, in: Norfolk Archaeology
Journal XXXVI pp. 23-38.
 Dymond, D. (1985): The Norfolk
 Embleton, R. & F. Graham (1984):
Hadrians Wall in the days of the
Romans, esp. pp. 126-7.
 Barnatt, J. & K. Smith (1997) :
The Peak District, esp. p. 53.
 Further details can be found at: http://www.hjsmith.clara.net/3943.htm.
 Any information on an earthwork in this
area would be gratefully received.
 Basset, S. (1989): In search of the
Origins of Anglo-Saxon kingdoms, esp. pp. 25-6.
 Further details can be found at: http://www.cpat.org.uk/projects/thisyear/progress.htm#929.
 Bowen, H.C. (1990) 'The archaeology of
 Dark, K. (1994): Civitas to Kingdom,
British Political Continuity 300-800, Studies in the
Early History of Britain, esp. p. 117.
 Burrow, I. (1981): Hill-forts after
the Iron Age: the relevance of surface fieldwork in
G. Guilbert (ed) Hill-fort Studies, esp. p.
 Fox, C. (1955): Offa's Dyke, a field
survey of the western frontier-works of Mercia in the
seventh and eighth centuries AD.
 Blake, S. and S. Lloyd (2000): The Keys
to Avalon: the true location of Arthurs Kingdom
 Hill, D. & M. Worthington (2003):
Offas Dyke: History and Guide.
 Dark, K. (1994): Civitas to Kingdom,
British Political Continuity 300-800, Studies in the
Early History of Britain, p. 125 and p. 150.
 Hamerow, H. (2005): The earliest
Anglo-Saxon kingdoms in: Fouracre (ed): The
New Cambridge Medieval History: c500-c700 AD, p.
 Weale, Weiss, Jager, Bradman and Thomas
(2001): Y chromosome evidence for Anglo-Saxon Mass
Migration, in: Molecular Biology and evolution 19
(7) pp. 1008-1021 and Goldstein Goldstein, prof. D. et al
(2003): A Y chromosome survey of the British
Isles. Current Biology Vol. 13 (11) pp 979-984.
- Barnatt, J. &
K. Smith (1997) : The Peak District.
- Basset, S. (1989):
In search of the origins of Anglo-Saxon
kingdoms, in: Basset, S. (ed) (1989):
The Origins of Anglo-Saxon kingdoms.
- Blake, S. and S.
Lloyd (2000): The Keys to Avalon: the true
location of Arthurs Kingdom revealed.
- Bowen, H.C. (1990)
'The archaeology of Bokerley Dyke'.
- Burrow, I. (1981):
Hill-forts after the Iron Age: the
relevance of surface fieldwork in G.
Guilbert (ed) Hill-fort Studies.
- Dark, K. (1994):
Civitas to Kingdom, British Political Continuity
300-800, Studies in the Early History of Britain.
- Dymond, D. (1985):
The Norfolk Landscape.
- Embleton, R. &
F. Graham (1984): Hadrians Wall in
the days of the Romans.
- Fox, C. (1955):
Offa's Dyke, a field survey of the western
frontier-works of Mercia in the seventh and
eighth centuries AD.
- Goldstein, prof. D.
et al (2003): A Y chromosome survey of the
British Isles. Current Biology Vol. 13 (11)
- Hamerow, H. (2005):
The earliest Anglo-Saxon kingdoms in:
Fouracre (ed): The New Cambridge Medieval
History: c500-c700 AD.
- Hill, D. & M.
Worthington (2003): Offas Dyke:
History and Guide.
- Moxham, R. (2001):
The Great Hedge of India.
- Wade-Martins, P.
(1974): The Linear Earthworks of West
Norfolk, in: Norfolk Archaeology Journal
XXXVI pp. 23-38.
- Weale, Weiss,
Jager, Bradman and Thomas (2001): Y
chromosome evidence for Anglo-Saxon Mass
Migration, in: Molecular Biology and
evolution 19 (7) pp. 1008-1021. A presentation of
the above source can be found at: http://www.ucl.ac.uk/tcga/presentations/ASdemo/AS-26-11-03b.html
Age Dykes is Copyright ©2006 Erik Grigg, used
to: Erik Grigg