ROMAN URBAN TOPOGRAPHY in Britain and the western Empire

Marsden: London in the 3rd and 4th centuries
Fig 74 London: collapsed roof tiles from the east wing of the dwelling adjacent to the small bath building at Billingsgate;
probably early 5th century
appropriate in that century. A mint was operating there
until about 326, and it was the seat of the Bishop in the
recently established Church. At some time the city was
renamed Augusta, presumably in recognition of services;
and, according to the late 4th-century Notitia Dignitatum,
the officer in charge of the Treasury was located in
London, even though the mint had closed down more
than half a century earlier.
The late Roman defences have provided a wealth of
information about what must have been an overriding
problem during the latter half of the 4th century - attacks
from barbarian raiders. These defences have been considered
in detail in several recent publications and the
conclusions are merely summarized here (Maloney 1983,
104-17). The first hint of a problem may be the construction
of a defended watch tower at Shadwell, probably in
the late 3rd century. A riverside defensive wall was next
built in London, which in places contained reused stones
and elsewhere did not. Much of the wall was constructed
on a foundation of chalk and oak piles (Fig 72)) and had a
carefully-built superstructure of unused ragstone, but at
the west end, at Blackfriars, there was no such foundation,
and the superstructure contained many reused carved
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stones from demolished religious buildings and monuments
(Fig 73). Maloney has argued that the differences in
construction can be accounted for by different gangs of
builders working with materials from different sources.
The present writer, however, has argued that these
probably reflect two distinct building phases, the first in
which there was access to the ragstone quarries in Kent,
the second, perhaps much later, when this was no longer
possible and buildings in the city were demolished to
provide the materials. It is agreed that two phases of
defensive wall existed on the waterfront at the south-east
corner of the city in the present Tower of London. The
earlier wall was founded on chalk and oak piles, and the
later wall, containing reused building materials, dated
from the last years of the 4th century (Goodburn 1978,
453). The existing landward defences in the eastern half of
the city were also strengthened with solid external towers
(‘bastions’), built from reused materials. On coin evidence
from around Bastion 6 these are believed to date from the
period 35 1-75, as was a broad defensive ditch into which
the bastion projected.
There is little archaeological evidence of the final stage
of Roman London and its apparent demise during the first