The boundaries of empire

The expansion of the empire by the first Augustus had come to an abrupt end in 9 CE when, in the course of stabilising Roman conquests in Germany, the Roman commander Publius Quinctilius Varus lost most of three legions at the Battle of the Teutoburg Forest, just north of the modern town of Osnabrück. It was a defeat that ranked in Roman imagination with the disaster at Cannae during the war against Hannibal, and lurid stories were told of how captured soldiers were sacrificed in barbaric rituals and how the gales and pouring rain made the massacre worse. It was said that the helpless Romans could not fire their arrows, throw their javelins or even wield their soaking shields. In the end, the casualties came to not far short of 10 per cent of the Roman armed forces; the remains of some of them, plus their pack animals, have recently been discovered on the site, including skulls with traces of deep head wounds. The victorious enemy was a German rebel, Arminius (‘Herman the German’, as he is now affectionately known), a man who had served in the Roman army and whom Varus had trusted as a loyal friend; Arminius tricked Varus into the ambush after saying that he was going off to raise local support for the Romans. As on other occasions, the most effective opponents of the legions were those whom the Roman themselves had trained.

Augustus had been planning to expand Roman territory into eastern Germany beyond the river Rhine. Clear signs of his intentions have been discovered over the past twenty years in the excavations of a half-finished Roman town, at Waldgirmes, 60 miles east of the river; its central Forum was already constructed, complete with a gilded statue of the emperor on horseback. It was never finished because after the disaster Augustus gave up plans for more conquests, withdrew westwards and at his death left instructions that the empire should not be extended any further.

Those instructions were not, however, quite so simple. For, as we have seen, Augustus also left a template for imperial power that was founded on conquest and on traditional Roman military prowess. And he bequeathed to his successors, and to the Roman people, a vision of the Roman Empire extending over the whole world. Could Jupiter’s prophecy in Virgil’s Aeneid, that the Romans would have power ‘without limit’, be conveniently shelved just because of a single disaster? That was hardly the spirit of Cannae.

For the next 200 years, until the end of the second century CE, those two incompatible visions of empire – consolidation versus expansion – coexisted surprisingly easily. There were a few additions to Roman territory. Claudius, for example, compensated for his decidedly unmilitary image by taking the credit for conquering Britain and celebrated the event with a triumphal procession in 44 CE, the first in almost thirty years. This had considerable symbolic value. It was the first Roman conquest in those strange lands that lay beyond the Ocean (otherwise known, in this case, as the English Channel) and turned Julius Caesar’s temporary foray on to the island a hundred years earlier into permanent occupation. But it was hardly expansion on a grand scale, and over the next decades it proceeded northwards to Scotland very slowly indeed. The careful assessment by the geographer Strabo, writing in the early first century CE, of the viability of annexing Britain is in fact a telling illustration of a newly cautious imperial culture. After reviewing the characteristics of the Britons (tall, bandy-legged and weird) and the resources of the island (including grain, cattle, slaves and hunting dogs), he argues that the cost of the garrison would outweigh any tax revenue that would accrue. But Claudius needed the kudos.

88. The head of the gilded horse from Waldgirmes – here seen in conservation – is a clear sign that before the military reverse in 9 CE the town was being planned as a major centre, with a full complement of characters (including Augustus himself on horseback). The town has been excavated in its half-finished state.

Only Trajan’s campaigns led to any significant expansion of the empire: through 101 and 102 CE he conquered Dacia, part of what is now Romania, in the operations that are depicted in detail on his column; between 114 and 117 CE he invaded Mesopotamia and went beyond, as far as modern Iran. This was the furthest east that Roman power was ever formally to extend, but not for long. Within days of coming to the throne in 117 CE, Hadrian abandoned most of the territory. The success was celebrated in a peculiarly bizarre triumphal procession. As Trajan had died on the way home, an effigy took his place in the triumphal chariot – and anyway, the conquered lands had already been handed back.

Many obstacles slowed down foreign conquests. The instructions of Augustus were one thing, but few posthumous wishes hold as much weight as the dead had hoped for while alive. The end of the competitive Republican political culture was more important. The emperors, who claimed the glory of military success whether they participated in the fighting or not, were mainly competing with their dead predecessors: a much less intense rivalry than that between, say, Sulla and Marius or Pompey and Caesar. This went hand in hand with a growing sense that the empire might in practical terms have boundaries, even if the extravagant prophecy in the Aeneid was never forgotten. That did not mean a fixed frontier in a precise sense. There was always a fuzzy zone where Roman control faded gradually into non-Roman territory, and there were always peoples who were not formally part of the provinces of the empire but nevertheless did what the Romans told them to, on the old model of obedience. That is why modern maps that claim to plot the edges of the empire in a simple line can be more misleading than helpful. But edges were gradually becoming less fluid and more important, as the wall constructed in northern Britain on the orders of Hadrian suggests.

89. On Trajan’s column the army appear as an efficient military machine, as much concerned with logistics as with slaughter. Here the troops are engaged in clearing forests in Dacia, their fort behind them.

Hadrian’s Wall, as we call it, stretched for more than 70 miles, right across the island from one coast to the other. Its construction was an enormous investment of military man-hours – but it is surprisingly hard to know what exactly it was for. The old idea that it was a defensive structure to keep the ‘barbarians’ out is unconvincing. It is true that the one ancient writer to mention its construction – an anonymous biographer and fantasist writing at the end of the fourth century CE (though for some unknown reason he pretends to be writing a century earlier) – refers to Hadrian ‘separating’ Romans and barbarians. But it could hardly have deterred any reasonably spirited and well-organised enemies who were keen to scale it, especially as much of it was built only of turf, unlike the solid stone sections that star in most photographs. Without a walkway along the top, it was not even well designed for surveillance and patrol purposes. But as a customs barrier, which is one recent suggestion, or as an attempt to control the movement of people more generally it seems a more hefty construction than was necessary. What it asserts is Roman power over the landscape while also hinting at a sense of ending. It may be no coincidence that other, rather less dramatic walls, banks and fortifications were developed in other frontier zones at roughly the same period, as if to suggest that the boundaries of Roman power were beginning to take a more physical form.

No one, however, who looked around Rome and many other cities of the empire could possibly have guessed that the project of world conquest had been dampened. Images of Roman victory and barbarian defeat were everywhere. Diplomatic deals with inconvenient neighbours were greeted with spectacular displays, as if they had been achieved by force of arms. After a rather inglorious peace agreement with Tiridates, the king of Armenia, Nero persuaded him in 66 CE to travel the thousands of miles to Rome to receive his crown from the emperor himself – who was dressed up in the costume of a triumphing general and is reputed to have covered the whole of the Theatre of Pompey in gold leaf for the day, to make it literally dazzling. Victories in defensive wars against internal enemies, rebels and invaders were commemorated as if they were glorious military achievements fought on Rome’s terms. The Column of Marcus Aurelius, for example, finished in 193 CE and towering those careful few metres above its Trajanic rival, celebrates campaigns that were a successful but extremely costly response to a German invasion. And everywhere there were statues of emperors in splendid suits of armour, and images of conquered, bound and trampled barbarians. Perhaps that was the easiest way to reconcile the conflicting legacy of the first Augustus: art and symbol could usefully compensate for the fact that in real life there was less trampling of barbarians now going on.

90. Hadrian’s Wall, whatever its original purpose, still clings to the tops of hills in north England. It was probably more symbolic than a defensive barrier; it could not have been hard to scale. But it surely represented some kind of boundary marker.

91. A classic image of Roman military power. The first Augustus, on the left, with an eagle at his feet (a symbol of the legions) is paired with a figure representing ‘Victory’ on the right. Between them is a suit of armour that was a trophy of military victory (Fig. 41) and squashed beneath a naked prisoner, his arms bound behind his back. This is one of a series of sculpted panels, depicting Roman emperors and their empire, from a sanctuary in honour of the Augusti at Aphrodisias in modern Turkey.