AN UNDERDEVELOPED ECONOMY 83forced on farmers, insofar as they had to provide the army with supplies, or
alternatively, in areas lacking a substantial military garrison, produce goods
that they could sell to raise money- taxes. This was exploitation, and in
aggregate exceeded anything witnessed previously in the Mediterranean
world. The main countervailing factor was the opportunity for profi t
provided by the existence, and for some farmers and traders the accessibility,
of those large and stable groups of consumers, the residents of Rome and
the frontier legions. Of all the commodities needed by inhabitants of Rome,
only grain was provided and distributed by the state for most of our period,
and, what is more, in insuffi cient quantities to feed the total population of
the city. Moreover, the frontier army was not entirely provided for by means
of tax or requisitions, compulsory and unpaid for, exacted far away or close
at hand.^21
Urban populations throughout the empire formed additional, multiple,
focal points of consumer demand. The period of the Principate saw urban
growth, for example in the Spanish and African provinces, and this may be
taken as an index of the economic development of the countryside. A large
number of non- productive consumers were supported by increased food
production. The city was the seat of social, legal and religious amenities, the
centre for the processing of primary products and the production of craft
goods, and the market centre for the sale and distribution of locally produced
and imported commodities. These constructive functions of the city have to
be set against its fundamentally exploitative role: it was the city which as the
agent of central government supervised the taxation system, adding its own
burdens on the rural population in the form of fi nancial demands and
personal labour services. It was the city to which the fl ow of rural rents was
directed, in its function as the base and consumption centre of the large
landowners. There was no radical readjustment of the priorities of the urban
elites away from the traditional goals of conspicuous consumption, social
status and political honour toward profi table investment.^22
The character and scale of the demands of central and local government,
and the opportunities for production for and sale in a sizeable market,
varied spatially and over time. The reactions of rural populations were
similarly diverse. Intensifi cation (through extension of the cultivated area,
shortening of fallow, higher labour input) and specialization (in particular,
higher investment in cash crops) were more widespread responses than
technological innovation to external demands and market conditions. The
Romans in north Africa built on indigenous farming techniques, even in the
vital area of water conservation and utilization.^23 Britain under the Principate
is now thought to have witnessed at worst stagnation, at best the diffusion
of techniques that had already made an initial impact on agriculture.^24 The
large granaries, mechanical mills and exotic plants that appeared in Britain
in our period have implications for distribution and consumption rather
than agricultural productivity, and they were received rather than developed
indigenously in the province. Gaul presents a contrast, at least on the surface.