Romeâs soldiers by ten to one: a guess which envisages a compact corps of full-timers facing the vast potential of a prehistoric world in which all were part-time warriors.
Romeâs erratic expansion had left anomalies which Augustus resolved to correct. Spainâs north-west corner, the Alpine lands and much of the Balkans still lay outside the empire and would be dealt with in turn. A serious underrating of difficulties beyond the Rhine would then entice Augustus eastwards. Our second Episode recounts the disastrous outcome in Germany: the first, clear, large-scale failure of Roman imperial expansion. The shock of this rebuke led to the famous advice, contained in Augustusâ will, that the empire should not be expanded further. In deference to his stepfatherâs wish, Tiberius turned to a foreign policy based on diplomacy, and with the exception of the British venture (described in Episode Three), the carrot would prevail till the end of the 1st century, when Trajan brought back the stick. Nevertheless, despite inconsistencies between one ruler and the next, Rome was gradually turning her back on adventurism: not only because of the absence of easy victims or dangerous enemies, but also because defence costs, coupled with economic stagnation, were reducing the means to attain more distant and difficult territorial goals.
A corollary to the cessation of expansion would be an armed frontier, soon to evolve along the Rhine and Danube. It would continue to be strengthened throughout the period and be joined by others in the Near East and North Africa. This represented an exchange of the informal boundaries of the Republican period, held by treaty and supported by bribery or menace, for a precise line of exclusion guarded by Roman soldiers. The barbarians would be allowed through its checkpoints in time of peace and in numbers acceptable to the Roman authorities, providing entry was in daylight, unarmed and after payment of dues. 8 Though the army would continue to patrol the near Barbaricum, gathering intelligence, mediating in disputes and paying stipends to friendly chieftains, the frontier could now be sealed at a momentâs notice. However, that the mistress of the world should even consider hiding behind barriers suggests deep changes in attitude, whose origins are also described in Episode Two: a recognition of the size of the outside nations, an acceptance that the gulf between those inside and outside the empire was unlikely to be bridged and barbarian envy unlikely to be assuaged. Time confirms this pessimism. The centuries offer no example of a frontierâs dismantling because improved relations made it unnecessary; or of voluntary fusion between the empire and its neighbours brought about by the onset of goodwill.
The First Episode sees the poet Ovid looking from the wall of a Black Sea outpost onto savage but skilful horsemen. This exemplifies the security problem of antiquity. On the one hand, a cultural gap and disparity of wealth between the classical and barbarian worlds too big to promise indefinite peace; on the other, advantages in military technique too small to guarantee a permanent Roman lead. Furthermore the pax Romana, with it laws against the bearing of arms, created a state whose civilian majority would forget how to fight.
The situation described by Ovid will not be revived till the 16thâ19th centuries, when the age of exploration takes Europeans across oceans and the Old and New Worlds collide. Most obviously, his vision of mounted archers circling the walls reminds one of Indians round a paleface stockade. But the comparison is unfavourable to Rome in two respects: the American settlers had firearms; and their support, in terms of numbers migrating from the motherlands, was almost limitless. Romeâs lacklustre technology would never put a decisive weapon into her soldiersâ hands; and population pressures would work not outwards against the barbarians but