22 THE ROMAN EMPIRE
it a bulwark for Syria. But the facts themselves show that it is a source of
continual wars for us, and of great expense. For it provides very little revenue
and involves very great expenditure; and having extended our frontiers to
the neighbours of the Medes and Parthians, we are constantly so to speak at
war in their defence’ (75.3.2–3). Dio’s words were prophetic, for within a
few years the last of the Severans, Alexander, marched east to inaugurate an
apparently never- ending cycle of armed confrontations with the aggressive
Sassanids, who had lately risen from the ashes of the Parthian dynasty and
were determined to restore the ancient Persian empire in all its former glory.
Persia/Parthia was a case apart. Most emperors, whatever the nature of their
offi cial pronouncements, valued consolidation and stability above expansion
and concomitant insecurity. The limes , a strategic system based on linear
frontiers, its characteristic features regular forts, walls, palisades, fences and
roads, was a product of this preference.
The Roman empire, then, extended far beyond the Mediterranean world.
Yet throughout the period of the Principate, from about 27 BC to AD 235, the
political axis and cultural base of the empire were to be found in the
Mediterranean.
Rome, Italy, and the political elite
Rome in the age of Augustus was the seat of emperors, the court and
administration and the residence of close on a million people. Rome was
essentially a parasite city, feeding off the manpower and wealth of Italy and
the numerous provinces that made up the Roman empire. The dramatic
growth of the capital city in the two centuries before Augustus, in the course
of which its population may have quintupled, was achieved by high levels of
immigration of destitute Italian peasants and enslaved provincials. Under
the Principate, the infl ux from largely provincial sources continued and had
to continue at a signifi cant, if lower, rate, if the population was to stabilize
at its Augustan level. Again, the expensive grain distributions, public works
programmes and entertainments of the city of Rome were fi nanced from
imperial taxes and rents from public properties carved out from the territory
of other states.
These revenues were drawn in large part from the provinces. Italy was
not a province and was exempt from the direct tax on property and persons.
This privileged status was retained until the end of the third century when
Diocletian introduced a provincial administration into Italy and imposed a
property and capitation tax.
Italy’s special status was however gradually undermined in the course of
the Principate by the infl ux of upper- class provincials into the senate and
into the second rank of the Roman aristocracy, the equestrian order.^8 By the
early third century Italians had lost their absolute majority in both orders.
Moreover, provincials had replaced Italians as emperors by the turn of the