Causes and explanations

There is no more vivid symbol of Rome’s changed relationship to the outside world in the early fourth century BCE than the vast wall erected around the city in the years after the Gauls left, with a perimeter of 7 miles and in places as much as 4 metres thick. It was simultaneously a mammoth building project (more than 5 million manhours of labour in the construction, according to one estimate) and a boastful symbol of Rome’s prominence and place in the world. There is no doubt, as both ancient and modern historians agree, that it was around this time that Rome’s military expansion outside its immediate neighbourhood began. Nor is there any doubt that the expansion, once started, was sustained more than anything by the resources of manpower that came with the alliances that followed its victories.

But what caused the change in the first place is a tricky question. What happened in the early fourth century BCE to start this new phase of Roman military activity? No ancient writer hazards an answer, beyond the implausible idea that the seed of world domination had somehow been planted. Maybe the invasion of the Gauls produced in the Romans a determination not to be caught out like that again, to take the offensive rather than being forced on to the defensive. Maybe it took only a couple of lucky victories in the endemic fighting of the region, followed by a couple of alliances and the extra manpower they brought, to ignite the process of expansion. Whatever the case, it seems likely that the dramatic changes in domestic politics had some part to play.

So far in exploring this period, I have largely kept the internal history of Rome separate from the story of its expansion. It makes for a clearer story, but it tends to obscure the impact of politics at home on relations further afield, and vice versa. By 367 BCE, the Conflict of the Orders had done something far more significant and wide-ranging than simply end political discrimination against the plebeians. It had effectively replaced a governing class defined by birth with one defined by wealth and achievement. That is partly the point of Barbatus’ epitaph: patrician though the Scipio family was, what counts here are the offices he held, the personal qualities he displayed and the battles he won. No achievement was more demonstrable or more celebrated than victory in battle, and the desire for victory among the new elite was almost certainly an important factor in intensifying military activity and encouraging warfare.

Equally, it was power over increasingly far-flung peoples and the demands of a conquering army that drove many of the innovations that revolutionised life in Rome itself. One important example of this is coinage. From early in its history, the city had a standard system of determining monetary value by weight of metal; this is evident in the Twelve Tables, which assess penalties in units of bronze. But there was no coinage as such until the end of the fourth century BCE, when ‘Roman’ coins were first minted, in South Italy, probably to pay for warfare or road building there.

More generally, if we were to ask what transformed the relatively simple world of the Twelve Tables into the relatively complex world of the year 300 BCE, the most influential factor would surely be the sheer size of Rome’s dominion and the organisational demands of fighting on a large scale. Simply the logistics of transport, supply and equipment entailed in mounting a campaign of 16,000 Romans (to use Livy’s estimate), plus allies, would have demanded an infrastructure unthinkable in the mid fifth century BCE. Although I have tried to avoid such modernising terms as ‘alliance’ and ‘treaty’ when referring to Roman activity in the fifth century BCE, the network of Roman connections throughout the peninsula and the different definitions of Rome’s relations with different communities by the end of the following century make those terms much less inappropriate. Roman military expansion drove Roman sophistication.

The family tomb of Scipio Barbatus now looks grandly archaic, and – with its coarse local stone, rather crudely carved decoration and slightly antiquated spelling (consol instead of consul, for example) – it might well have seemed quaintly old-fashioned to any Roman who entered it in the first century BCE. But in his day, Barbatus was part of a new generation who defined a new way of being Roman and a new place for Rome in the world. His descendants took that even further, and it is to them we now turn.