Nah I think nationality would be almost implicitly obvious (e.g. due to clothing), the relationships would be much more on a personal level, first name basis an

Nah I think nationality would be almost implicitly obvious (e.g. due to clothing), the relationships would be much more on a personal level, first name basis and such, or the historically appropriate equivalent of, well, "habibi" or "buddy". But I'd expect that two interacting merchants would definitely know of each other's names, as semi-contractual epistles of orders and corresponding shipping invoices were very much a thing (actually already since Sumer). Not to mention that when you met someone back then, from what I understand, the idea would be that you would update each other on the stuff you knew about the world at large, sort of like a Fidonet where you got to walk to the next node: the time you spend with each other is precious, and ends up constructing a global grid of relationships and information. It's mindblowing to consider these past ages, and how all those people who just went on with the business of living and learning even without GPS or Wikipedia, and did pretty well regardless.