ROMAN URBAN TOPOGRAPHY in Britain and the western Empire

Salway: Geography and the growth of towns, with special reference to Britain
I earlier suggested a powerful streak of the rational in
the religious practices concerned with the choice of a site. I
should now like to look briefly at the other side of the same
coin: the side where the Romans thought they were
operating on scientific lines. Returning to our example
from Vitruvius about the setting out of a town relative to
the winds, we read (i-4.1-6) that
. . . if the town is on a coast and faces south or west, it
will be unhealthy, because the southern sky in
summer heats up as soon as the sun appears and
burns at midday. A western aspect is warm after
daybreak, hot at noon, and glows with the setting
sun in the evening. . . In summer everyone grows
weak from the heat as much in healthy spots as
unhealthy; and in the winter even the most unhealthy
places are better for the solidity given by the
cooling process. People who move from cold countries
to hot cannot endure the climate but fade away;
while those who go from hot regions to the cold of
the north lose nothing - indeed their health benefits
from it.
. . . all bodies are composed of the four elements,
heat, wetness, earth, and air, but there are different
mixtures according to the nature of the particular
creature. . . . If, then, one of these elements - heat -
predominates over the others, it destroys them.
On this argument one might expect there to have been a
great flourishing of the cities of the northern part of the
Empire, stimulated by a mass influx of literate hypochondriacs.
But we cannot win. Vitruvius goes on to argue
(i.6.2-3) that
Wind is air in constant motion, flowing here and
there without end. . . . By shutting out winds from
our houses we shall make our city healthy for those
who are already fit arid also help those who perhaps
suffer from diseases brought on by unhealthy locations
elsewhere. . .to become well again from the
mildness caused by excluding the winds . . . . In
unhealthy places, the air is polluted by being
constantly stirred up by the wind and debilitates the
sick day by day. A mild, thick air, however, which is
free from draughts and continuous movement,
restores their bodies by building them up with its
own unshifting steadiness and brings such people
back to health.
So Vitruvius would have the potential founder of cities
seek a cold climate with no draughts! On the whole, it
must have been easier to trust to the guidance of the gods
than follow the dictates of contemporary science. But the
point I am trying to make is that we cannot dismiss the
‘irrational’ (in the sense of irrational to us) in considering
why particular choices were made. Our problem is that we
very rarely have any evidence for the operation of such
factors. Our lesson must be always to allow for their
possible influence on judgements in the ancient world,
and consequently to be tentative in attributing reasons
based on modern ways of thinking for particular urban
foundations and their subsequent success or failure. Of
one thing we can be certain: once political, military, and
economic practicalities had pointed the Romans in a
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particular geographical direction, the clinching factor in a
decision is much more likely to have come from the livers
of sacrificial animals than from central-place theory.
The emphasis has so far been on the deliberate foundation
of towns and cities, but at this point it is appropriate
to digress briefly so as to deal with a source of confusion
that may be about to invade the terminology of our
subject. In a recent article on the origins of some major
Romano-British towns Crummy (1982) draws a distinction
between ‘those with newly-planned layouts’ and
‘those founded on the sites of military fortresses’. This
distinction is entirely valid in the context of that article,
but his subsequent use of the term ‘planned town’ (in
opposition to ‘reused fortress’) is only too likely in the
hands of the careless to leave the impression that Exeter or
Gloucester, for example, were not ‘planned’ in the more
generally understood sense.
It has to be remembered that the deliberate - in
modern terms ‘planned’ - urban foundation was extremely
common in the ancient world. The tradition in the
western Mediterranean certainly goes back to the numerous
Greek colonies of the 8th century BC and onwards:
Syracuse or Pithecussae, for example, Ampurias, Marseilles,
or the well-known lesser sites that lie along the coastal
sea-route on the Mediterranean shore of Gaul. Indeed, so
much was this the norm that it was often felt necessary to
provide a foundation story - usually with a heroic
founder - for settlements whose origins were in reality
much more obscure, probably often being organic rather
than the result of a deliberate act. In the East these stories
extended especially far back and frequently starred Greek
heroes wandering, like Odysseus, after the Trojan Wars.
The foundation story of Rome itself contained just such a
Trojan War element, and after the tradition had been
hallowed by Vergil and hammered home by Augustan
propaganda, emperors certainly came to regard the deliberate
foundation of cities - planned foundation - as a
prestige activity. This applied as much to refoundation as
foundation - for example, Constantinople imposed on
existing Byzantium, or perhaps, if one may come down
from the sublime, the new street grid superimposed on
Silchester. A ‘green-field’ site (to use the current planning
jargon) was undoubtedly easier to handle, but we should
not imagine that in Roman terms the conversion of Exeter
into a civil city was any less planned than the building of
Caistor-by-Norwich. In many ways, indeed, an abandoned
legionary fortress must have resembled a ‘greenfield’
site much more than, for example, Aix-en-Provence,
which by the time of its Augustan refoundation as Colonia
Julia Augusta Aquis Sextiis could already trace its Roman
occupation back a century to the establishment of the first
permanent garrison in Gaul.
How geographical factors came into the actual choice of
sites for the deliberate foundation of cities, and how ideas
about them influenced their success by attracting willing
colonists (and encouraging the conscripted or directed
colonist to contribute to that success by staying), is not as
simple as might at first appear. Vitruvius has given some
reasons of common sense - or apparent common sense -
and to these we may add some other factors that must have
been obvious. The interaction between what one might
call the ‘strategical’ geographical-cum-political elements
and the ‘tactical’ can be demonstrated by returning to
Provence.