by Angus
Konstam
The background
When the Romans came to
Scotland in AD 80, they knew little or nothing about the Celtic
tribes who lived in the region. Faced with invasion, the tribesmen of
the lowlands either submitted to Roman occupation or withdrew to what
they thought was the safety of their hilltop forts. This proved a
costly mistake, as the two largest forts in the area fell to the
might of the Roman army and its siege artillery. The tribes who
resisted (known by the Romans as the Selgovae and the Novantae) were
brought to their knees by the end of the year, and the Roman Governor
Agricola consolidated his northern frontier along the line of the
Forth and Clyde rivers. The area was completely pacified by the start
of AD 82. So much for the defensive protection of the lowland
hillforts. Further north a fresh challenge awaited Agricola, as he
planned to lead his armies into eastern and north-eastern Scotland,
beyond the Firth of Forth. These Celtic tribesmen had used their
fortified bases in what is now Stirlingshire to harry the Romans, and
Agricola had had enough. In AD 83 he launched his legions in an
expedition of conquest, cornering the local ‘Caledonian’
tribesmen in battle at Mons Graupius (84) and inflicting a decisive
defeat on his opponents. During the advance his flanks were secured
by a series of Roman auxiliary forts designed to prevent Caledonian
movement out of the Highlands. His fleet sailed north as far as
Orkney, forcing the submission of the coastal communities they
encountered.
Although the Roman tide receded due to commitments elsewhere, the
threat of punitive attacks against the Caledonian tribes continued,
forcing the local Celts to maintain strong defensive positions and to
ensure their near-constant readiness for war.
The Roman defensive
line along the Forth–Clyde line was abandoned around AD 100, and
the frontier was re-established between the River Tyne and the Solway
Firth, a position which was defended during the reign of the Emperor
Hadrian (AD 117–138). The Romans returned north for a time during
the reign of the Emperor Antonius Pius (AD 138–161), and the
Antonine Wall was built along the old Forth–Clyde line, before it
too was abandoned after the death of the Emperor. From that point on
Hadrian’s Wall marked the northernmost frontier of the Roman
empire. Although the tribes immediately to the north of the wall were
relatively peaceful, those further north were more hostile. At the
start of the 3rd century AD the Emperor Septimus Severus (AD 193–211)
led punitive expeditions against the Caledonians, as did the Emperor
Constantius I Chlorus (AD 305–306) a century later. It was during
this last expedition that we first hear of the Caledonians being
referred to as the ‘Picts’, or painted people. Historians
generally take this date as the mark that divides the era of the
Picts from that of their Caledonian forebears, and provides a
convenient finishing point for our study.
In early Celtic Scotland, there were three main types of
fortifications in use during this period: the brochs, the duns and
the hillforts.
Towers in the north: the brochs
The Broch of
Gurness stands on the shore of a stunningly beautiful bay and sound
in Orkney. It was built at some point between 500 and 200 BC, and the
broch itself formed part of a defensive site that included a village
and a series of encircling ramparts and ditches. The brochs of Iron
Age Scotland were a virtually unique solution to the defensive
requirements of their builders. Spectacular even in ruin, these
structures often combined the functions of a defensive retreat with
that of a communal focal point. They protected the local people from
petty bandits, raiding war parties and on occasion, from full-scale
invasions. As such they often formed the nucleus of small
communities, or were located close to existing settlements. This
means that any true study of them as fortifications needs to be
combined with a look at the communities they served, and the people
who built them. From there we can look at the fortifications which
succeeded them, and which provided defensive strongpoints for the
Picts, who inherited the land from the Iron Age broch-builders.
A broch was an imposing circular fortification built using
drystone walling. This meant that no mortar was used, but the
irregularly shaped stones were chosen so that they fitted roughly
together. They were tall, grim, windowless structures, containing a
passage within the walls which eventually led to an upper rampart.
The only entrance was a small, easily-defensible doorway at ground
level. Two walls were separated by passageways, stairs and galleries,
which eventually led up through the walls to the circular upper
parapet, where the defenders could rain missiles down on the heads of
their attackers. While the Broch of Gurness is considered an early
example of the genre, the Broch of Mousa in Shetland is probably the
most intact example of a later (and more classical) broch structure.
Precursors of the earliest brochs were probably the strong circular
houses whose ruins are located in the same geographical area as the
brochs.
Almost all brochs are located in the north and west of Scotland in
Caithness, Orkney, Shetland and Skye, while a few others were built
further south. The majority of them are concentrated in Orkney,
Shetland and Caithness. Dating evidence suggests that most were built
between the start of the 1st century BC, and the late 1st century AD,
although this has been questioned due to the equivocal dating
material so far discovered. Further evidence suggests that
‘proto-brochs’ or precursors to the classical broch structure
could have been built as early as the 6th century BC, while we know
that some remained in use until at least the early 3rd century AD, if
not later. Although we know a lot about the structures themselves,
and we can analyse their defensive qualities, we know very little
about who exactly built them, and why. Obviously numerous theories
have been proposed, and it was only recently that archaeologists
reached a general consensus on what may have happened.
Clearly,
they were designed for defence. The Broch of Mousa alone stands to a
height of some 13 metres (40 feet), and would have been a proof
against all but the most determined assault, unless the attacker had
Roman-style siege artillery. The low narrow entranceway made it
difficult to batter down the door, and the walls of Mousa were too
high for ladders. The hollow interior was probably roofed over, and
was large enough to house livestock, provisions and people until the
threat had passed. We know little about who the threatening attackers
might be, but Celtic, Roman or German raiding parties might have come
to these areas in search of slaves. Although not impregnable, smaller
brochs would have guaranteed that an attack against them would have
been costly, and thus they acted as a form of deterrent against any
potential aggressor.
Until comparatively recently, brochs were sometimes referred to as
‘Pictish towers’, or even associated with the Norsemen (vikings).
While these links have been disproved, the terms indicate a general
lack of understanding of the brochs and the broch builders. We know a
certain amount about the late prehistoric people who lived in what is
now Scotland from their archaeological legacy. They were not Scots,
as that political entity post-dated the broch builders by a
millennium, but we have no alternative name to identify them by, as
no written records survive from this culture and period. The term
‘Celtic’ has been widely used to describe all the iron age people
of this period who inhabited most of Europe, including Scotland, but
some archaeologists baulk at using such a widely applied appellation.
As for the term ‘Pictish’, their time came later, and the Picts
have usually been identified with the inhabitants of north-east and
east central Scotland from the early 4th century, when the name first
appeared in Roman written records. The broch builders had been long
gone by then, and while the Picts may well have been the descendants
of these broch builders, archaeological information is unable to
prove a clear descent from one group to the other. Various theories
have been proposed, including ones where the Picts reached Scotland
from overseas, and similarly that the broch people were somehow
different from the pre-Celtic people who inhabited the rest of
Scotland.
It is probably true that the pre-Celtic people of Scotland
intermingled with later waves of Celtic migrants, but there is no
direct Celtic broch building tradition. It has been suggested that
while the rest of Scotland was overrun by the Celts, the broch
builders retained their independence, and fortified their
settlements. Whoever built them, their appearance coincided with the
arrival of the Celts, and their disuse began following the arrival of
the Romans in Scotland. Some archaeologists have given the broch
builders the clumsy appellation of proto-Picts, but this does the
earlier people a disservice. The broch builders displayed certain
qualities which were absent elsewhere in the Pictish homeland (which
included Orkney and Shetland), so although there are many theories,
there are few answers to the mystery of who these enigmatic people
were. It is possible that by the time the Pictish era, the local
population had effectively become as Celtic as the rest of Scotland.
Certainly we know that most brochs were abandoned at some point
during the 3rd century AD, which is close enough to the appearance of
the Picts as a distinctive people to suggest some link between the
two dates.
Blockhouses in the west: the duns
The term
‘dun’ is used to identify a particular type of small fort which
was built extensively all across south-western and western Scotland,
with the greatest concentration found in Argyll. These circular or
oval dry-stone structures were similar to brochs, but were much
smaller. While some were built on flat ground, most were constructed
on rocky outcrops or natural defensive positions to enhance their
defensive properties. Their walls were usually built using two thick
dry-stone walls, with a solid core of rubble used as infill between
them. Some used timber to lace the structures together (as was the
case with the first hillforts), but most had a smooth outer face,
devoid of timber reinforcements. In some examples the wall was
reinforced at the base to allow the construction of higher or heavier
structures. Like the brochs, the entrance was small and protected by
chambers to discourage battering attempts. A particularly impressive
example (the Dun of Leccamore, on Luig) even boasts an internal
stairway, and other design features suggest some form of correlation
between the broch builders and the defensive properties of these
smaller dun structures.
While some earlier timber-laced duns have
been dated to the 6th or 5th century BC, the majority appear to have
been built during the period after the Romans came to Scotland,
during the 2nd and 3rd centuries AD. Some show evidence of
occupation, abandonment and re-occupation, suggesting they were used
when the situation warranted it, and in more peaceful times they may
have been abandoned for more spacious and convenient settlements
nearby. They also show signs of a far longer occupation than the
brochs to the north or the hillforts to the south and east. Dun Cuier
on Barra was occupied until around AD 500, while Kildalloig in Argyll
appears to have remained in use as late as the 8th century. Unlike
the brochs or hillforts, most duns appear to have been little more
than fortified homesteads or farms, but they remained a feature of
the Scottish landscape for over a thousand years, and outlived both
other forms of early Celtic fortification.
Strongholds in the south: the hillforts
Nobody
knows how or exactly when the Celts reached Scotland. Towards the end
of the Bronze Age (around 700 BC), these newcomers began to arrive,
bringing the new technology of the Iron Age with them. These Celts
also introduced a new feature to the Scottish landscape. Over the
next eight centuries, hillforts would appear in various sizes, from
small fortified farms to full-scale fortified hilltop townships. They
provided refuge for the local Celtic communities who faced attacks
and raids from their neighbours. While well-designed to protect the
Celtic tribespeople from their own kind, they proved less effective
against the Romans.
Although the early Bronze Age defensive ring at Meldon Bridge in
Lothian is probably the earliest fortified site in Scotland, the
first hilltop fortifications appeared around 600 BC or slightly
earlier. These took the form of timber-laced fortified circles. In
some cases the ramparts were fire damaged during their period of use,
which allowed the sites to be carbon dated. While the dating range is
wide most appear to have been actively built or expanded during the
6th century BC or later. These timber-laced structures continued to
be built in Scotland until the coming of the Romans in the late 1st
century AD, although the style of the fortifications became more
elaborate with time. Timber-lacing was a technique used to stabilise
both earthen ramparts, stone walls or rubble infill by laying
horizontal wooden beams across the structure, binding it together. In
other words, the timber provided a massive framework which was filled
with stones and rubble, then faced with solid stone. A wooden walkway
and palisade were then built on top of this defensive perimeter.
Thick wooden gates protected the entrances to these hilltop
enclosures.
Surviving examples such as the stone and earthen wall of the
fortification at Abernethy in Perthshire (occupied during the 1st
century BC) show the surviving slots in the walls where these beams
were placed, and had rotted away. In cases where the forts were
destroyed by fire (probably during an assault), fire damage caused by
the burning timber has left its mark on the surviving stonework,
which has sometimes been fused together. In rare instances, the
remains of timber-lacing survives, such as at Kaimes Hill in
Midlothian. Timber-laced forts were built throughout central and
eastern Scotland and around the Moray Firth to the north, and this
distribution matches that of early Celtic finds such as axe heads
dating from the 7th century BC and later. This proves that the early
Celtic people who occupied central and eastern Scotland relied on
these types of fortifications for their protection.
The nature of these hillforts changed over time. In some cases,
the original timber-laced structures were replaced or rebuilt in
later periods. At Kaimes Hill a series of stone-faced ramparts
replaced these earlier defences, and a series of ditches were dug
around the perimeter to strengthen the position. One additional
refinement was the setting of a ring of pointed stones around the
outside of the wall, creating a disruptive obstacle which would
hinder any attackers. The trouble with timber-lacing was that the
timbers were difficult to replace once they rotted, or they could be
destroyed by fire with relative ease. Archaeological evidence
suggests that while timber-lacing continued to be used in Scotland
during the early Celtic period, the weakness of the design was
apparent to the builders. Consequently when the local Celtic tribes
of lowland Scotland were faced with the prospect of Roman invasion in
the late 1st century AD, many forts were strengthened and improved by
the addition of all-stone walls and the digging of ditches outside
the walls. In addition to their walls or earthen ramparts, most of
these defensive positions were topped by wooden palisades.
These forts were almost exclusively built on hilltops to impove
their defensive capabilities, and in many cases the walls enclosed
some form of interior settlement. Of some 1,500 fortified sites in
Scotland, the majority of these forts were located in lowland
Scotland, below the Forth–Clyde line. This surprisingly high figure
includes small fortified farmsteads and isolated stone structures
from the same early Celtic period. As some of these were built over
700 years before the Romans appeared, it comes as no surprise that
many had been abandoned for centuries by the 1st century AD, although
a handful remained in continuous use throughout their history. Unlike
the sprawling hillforts such as Maiden Castle in England, these
Scottish fortifications were small, and probably only served small
local communities. The two exceptions were Traprain Law and Eildon
Hill, both of which were substantial defensive positions, and the
latter containing over 300 roundhouses. This meant that in times of
danger, an entire tribe could seek refuge within its walls. One of
the problems with Scottish hillforts is the lack of available
information about their history. We rarely know how long they were
occupied or when, and what function they served apart from a
defensive one. It does seem that at least at certain periods, the
hillforts which enclosed settlements tended to be under continuous
occupation when the Romans appeared.
Another variant of the hillfort was the promontory fort, which was
found at various points along the east coast of Scotland, such as St.
Abb’s Head, Dunnotar and Urquhart (the last was actually on the
shores of Loch Ness, not the North Sea). All but the last were most
probably established as fortified sites well before 300 AD, but all
three were developed into major fortifications during the Pictish
period, and the last two were actual Pictish fortifications.
Similarly, the promontory at Burghead on the Moray Firth was
developed as a Pictish stronghold. In all three sites, elements of
the old hilltop fort designs were used, as the headland was cut off
from the mainland by a series of defensive walls and ditches. Again,
the Burghead fortification may have predated the start of the
historic Pictish period, but the lack of hard dating evidence makes
it impossible to say so with any certainty. Certainly the system of
three lines of earth and rubble defences and intervening ditches is
similar to that found in hilltop forts from 300 BC on, and we know
the Picts added an inner citadel to the fortified point at Burghead.
The spot was also a good anchorage, and it has been suggested that
Burghead was used as a Pictish base from which maritime raids were
launched down the coast into Roman Britain. Certainly there seems to
be a legacy of construction methods which linked the known Pictish
fortifications (Inverness, Dunadd, Dundurn, Dunottar, Dunkeld,
Clunie, Scone, Inveralmond and Forteviot) to the earlier hilltop
forts in the same area (Tayside, Moray and Grampian).
Summary
To sum up, although the Iron
Age landscape of Scotland is littered with fortifications, these can
be divided into three groups. The brochs of the northern and western
isles are virtually unique, and their design displays a high level of
architectural and military appreciation. To the south-west the duns
were smaller counterparts, and less likely to be situated in coastal
locations. These remained in use until well after the arrival of the
Scots from Ireland, and outlasted all but a handful of coastal
fortifications which were probably used by both the Celts and their
Pictish descendants in eastern Scotland. As for the rash of hillforts
in southern Scotland, the majority fell from use following the Roman
invasion of the late 1st century AD. Despite this, their methods of
construction were adapted for use by the Picts as well as the
Scottish peoples who inhabited the southern lowlands when the Romans
withdrew. Scotland is unique in that so many of its monuments are
still extant, and have been saved from centuries of development.
Although the region produced methods of early Celtic fortification
that were unique, any study of these defensive sites helps us
understand both the people who built them, and their Pictish or
Scottish descendants.
Further Reading
Armit, Ian,
Celtic
Scotland, Historic Scotland Publication – Batsford Press,
London, 1997
Breeze, David J.,
Roman Scotland, Historic
Scotland Publication – Batsford Press, 1996
Ritchie, Anna, and
Breeze, David,
Invaders of Scotland, Historic Scotland
Publication – HMSO, 1990
Ritchie, Graham and Anna, Scotland:
Archaeology and Early History, Edinburgh University Press,
1991
Ritchie. J. N. G.,
Brochs of Scotland, Shire
Publications, 1988
Sutherland, Elizabeth,
In Search of the
Picts, Constable and Co., 1994
Wagner, Paul, Warrior 50:
PictishWarrior AD 297–849, Osprey, 2002
