GDP map of the Roman Empire

[Jim Webster]

so in the Hellenistic world, a mixture of prestige, money opportunities and a flexible approach to the 'arrangements' used on a local level. In the Roman world more a case of pride/prestige and a solidification of 'this bit is mine'?

I'm not sure about the Romans and 'solidification' in that there is now evidence that the Romans had troops patrolling regularly beyond the line of the frontier, forts in Scotland north of the border (which obviously couldn't have been held against a hostile populace without armed convoys fighting their way through with supplies) seem to indicate fuzzy boundaries, there may have been Roman troops at the Nabataean Red Sea port of Leuke Kome. In North Africa the boundary seems to have relied of tribal leaders with Roman titles controlling areas inside and outside the Empire, and then you have the Ghassanids and Lakhmids contesting between them a broad border area

[Patrick Waterson]

The whole client king/client state system practised under the Roman Empire seems to have been an integral part of maintaining borders beyond the borders, so to speak.  As Jim points out, Hellenistic kingdoms also had degrees of 'in', where rule shaded down to influence and was blended with alliance.

[Imperial Dave]

fuzzy boundaries,

possibly the most dangerous kind of border for the empire

[Jim Webster]

fuzzy boundaries,

possibly the most dangerous kind of border for the empire

Yes, because they always tempt you to go that little bit further

[Imperial Dave]

fuzzy boundaries,

possibly the most dangerous kind of border for the empire

Yes, because they always tempt you to go that little bit further

Or think that if you ceded ground it was only temporary...

[Jim Webster]

fuzzy boundaries,

possibly the most dangerous kind of border for the empire

Yes, because they always tempt you to go that little bit further

Or think that if you ceded ground it was only temporary...

Merely stepping back to butt harder 

[Imperial Dave]

An opportunity to fill one's coffers

[Patrick Waterson]

Which incidentally might skew the GDP map.

[Imperial Dave]

good point...

GDP could therefore be very very (very) volatile!