I am finding this quite annoying.....
I am playing as Rome and have taken large swathes of North Africa.
Carthage keeps sending armies deep into my territory, sometimes three regions in.
In game terms this is hundreds of miles bypassing lots of cities along the way.
I am missing the old AGEOD concept of forifications "blocking" these raids.
Is there any such restriction on this behaviour?
At present there is no such thing as the extremeties of the Roman Empire beating off all invaders, they just march in when they please and strike at the regions way behind.