Today's Economic History: There is no such thing as the fall of the Roman Empire: "The Romans don’t sit down and have a grand plan to conquer the world...:
...or have particularly better tactics or equipment than their neighbours. But they have strength of manpower, and boots on the ground. The reason they have that is because they have an incorporating attitude to citizenship. When they conquer people, they bring them into the Roman project, so that they have an overwhelming number of troops. That is crucial, because it means their empire is built upon making people citizens.
I think that the extremely-sharp Mary Beard has gotten this... pretty completely wrong. Or, rather, that this is largely right for Rome from 400 BC to 200 BC--and pretty completely wrong thereafter. It looks to me as though relatively early in the 300s BC Rome:
- acquired its ethos of incorporation--that at least the elites of those they conquered immediately became Romans, with the privileges of citizenship and embedded in the patron-client wealth distribution networks--and
- acquired a political system in which the only road to success of any substantial sort was success in conquest.
Thus from the early 300s down to the time of Hannibal the consuls are always looking for a fight. When they win "Rome" grows. When they lose they either pay ransoms and tribute, or they double-down and mobilize more troops.
Very different processes are at work after 200 BC, however: Caesar did not conquer a Gaul of 15 million people in a decade because of "strength of manpower and boots on the ground". He conquered a Gaul of 15 million people with 50,000 post-Marian legionaries.