- Fortifications and Defence -
It should be acknowledged that, given the passage of centuries of erosion
and deposition, there is no straightforward way from the surface examination of
earthworks in many instances readily to distinguish between a deliberate desire for
fortification on the part of the original builders and enclosure primarily for other
purposes. The topographic setting of lines of enclosure may, however, offer some
assistance to speculation. Thus the now-diminutive and unexcavated banks which
define the site of White Meldon in Tweeddale District, Scotland, are surmised to have
been defensive not from their surviving stature but from their hilltop location on a
prominent summit (Royal Commission on the Ancient and Historical Monuments
of Scotland 1967): a 'high eminence' site, in Avery's terminology (1976: 8). In other
cases, such as Scratchbury (Wiltshire), the establishment of the defences well down-
slope, rendering much of the interior of the site visible from the adjacent lowland,
may indicate a largely non-military purpose (Bowden and McOmish, 1987, 1989)
(Figure 5.1). In many areas, including those dominated in more recent times by Celtic
speakers, the building of fortifications in broadly similar architectural traditions
continued well into the first millennium AD. Radiocarbon dates demonstrate
this unequivocally for Scotland, for example (Alcock 1987). Earlier sites were also
reoccupied and their enclosures remodelled in the Early Historic period, as at South
Cadbury in Somerset (Alcock 1972, 1982). The fortifications of Celtic Europe are
thus best regarded as a subset of a vast series, which is more extensive both in space
and in time.
The materials used in the construction of fortifications are dominated by those
standardly employed in temperate European proto history: timber, stone and earth
(Biichsenschiitz 1984; Audouze and Biichsenschiitz 1992). Reliance on wood,
particularly in cases where structural elements were exposed to weathering, may be
assumed to have produced fortifications generally of lesser durability; in some
instances, these seem to have been serviceable for a few decades at most. The focus
here on the architecture of fortifications mirrors the primary attention that has been
devoted to this aspect of them in the archaeological literature.
The fortifications fall into three basic categories: palisades; walls, intended to have
a near-vertical external face; and ramparts, in essence linear mounds fronted by an
artificial slope or glacis. Fence, wall and dump, as Hawkes (1971) would have it.
Walls include those of simple dry-stone construction, employing either surface-
gathered stone or quarried and, in some instances, roughly shaped blocks: on
occasion, these may be imported to the site, as for the eastern gate at Maiden Castle,
Dorset (Wheeler 1943). A variant form, marked by the presence of additional facings
within the thickness of the core, is sometimes termed the murus duplex, the descrip-
tor taken from Caesar's account of his subjugation of Gaul (De Bello Gallico II.29):
at Worlebury in Somerset walls built in this style reach II m in width (Figure 5.2).
Avery has proposed the descriptor 'shell construction' for this type of wall (1976:
14). Other examples, however, demonstrate substantial use of earth or even domestic
detritus in their cores, and considerable components of structural timberwork, as will
be discussed further below.
The most sophisticated achievement in terms of dry-stone architecture is that
represented by the hollow-wall construction employed in brochs, best considered
as a variant on the complex Atlantic round-houses of north-western Scotland
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