Some cities were back then were cosmopolitan and so was the military, he seems to conflate that with the modern situation. I am not completely puritanical about there being absolutely no foreigners. There has been exchange and meeting in most places throughout history. Cosmopolitanism is not something I would want for its own sake, that is all. In the modern sense, it is not just a little bit, there is an active drive to bring in all sorts of disparate groups and jumble them all up. We have a mono-culture being formed while some others keep their own culture and demand our accomodation. It is not going to work anyway. As for cosmopolitanism in the Roman empire, how did those German foederati work out for them? It benefited the Germans by giving them land, political clout, and coin, but the Romans got the bad end of the deal. They had to pay people that still had their drive to fight to protect their decadent empire. The Roman elites were short sighted and probably desparate to hold things together. Didn’t work out. Not something I want to do. Was there even a meaning to Roman identity at the end? Citizenship was widespread, the culture was spread out and in my opinion diluted. Was it worth doing away with the Roman people to form the empire? Empires are formed by a conquering group with powerful qualities and lots of drive. It inevitably gets diluted and weak after forming the empire and spreading out. This has been noticed by many historians. They end up being subsumed into the conquered and being conquered in turn, usually by “barbarians”.