INTRODUCING THE PRINCIPATE 17Aggressive warfare, wars of conquest, virtually came to an end after
Augustus. Britain was taken into the empire under Claudius (in 43), and
Dacia across the Danube by Trajan (in 106).^39 These were exceptions.
Roman emperors from time to time ‘remembered the Parthians’, more
particularly the disasters suffered at their hands by the armies of Crassus
(53 BC ) and Antony (36 BC ). The Parthian empire was invaded under Trajan,
Marcus and Verus, and the Severans. Temporary gains were made, and
additional embarrassing defeats avoided. Unquestionably the greatest
disaster suffered by the Romans and their subjects during the whole of the
Principate was a by- product of the second of these expeditions. The armies
of Marcus and Verus brought back from the East in 165 an epidemic disease
thought to be smallpox, which made inroads into the population of the
empire, reversing the slow and steady demographic growth of the preceding
two centuries, and disrupting production, exchange and tax- collection.^40
There were no Roman losses on any scale on the battlefi eld after the
catastrophic defeat of Quinctilius Varus, whose three legions were wiped
out by the Germans in AD 9.^41
Shaken by the disaster in Germany, Augustus left to his successors the
fi rm counsel that Rome should stay within its current boundaries. On the
whole they followed his advice. Emperors of the Principate could afford to
be ‘lazy’, given the absence of serious opposition, external or internal.^42 This
was partly good luck. Germanic tribes did not learn to combine against
Rome until the third century – the Marcomannic wars under Marcus
Aurelius (from 166 or 167) are an early sign that they were capable of doing
so.^43 Similarly, the threat from the East stepped up markedly once the Persian
Sassanids had replaced the Parthian Arsacids, again in the third century (in
226). But it was partly also the heritage of Augustus. He did not abolish war
(despite the grand gestures of the dedication of the Ara Pacis, dedicated in
13 BC , and the closing, more than once, of the doors of the temple of Janus,
symbolic of the end of warfare), but rather exported it to distant lands,
giving Rome, Italy and the inner provinces the chance to recover from the
destructive effects of decades of civil war, and in the long term to enjoy
relative order, peace and prosperity. In the literature emanating from the
more established and economically advanced provinces of the empire, in
particular the Greek- speaking East, the benefi ts of the pax Romana for
Rome’s subjects become a recurring theme.
A crucial move was the demobilization of the massive army left over
from the civil wars. Augustus was able to achieve this without resort to
proscription and land- confi scation in Italy, drawing on the spoils of the new
province of Egypt. In its place a professional army was recruited with
regularized terms of service. The state, that is, the emperor, took responsibility
for its welfare. The new- style army was despatched on a massive mission of
conquest, which added to the empire the whole of the Iberian peninsula, the
Alpine regions, Gaul up to the Rhine and the Balkans up to the Danube.^44
An aggressive foreign policy served as a distraction from the novelty of the