How do they know they are Roman?
Could be Babylonian, Persian, Assyrian, Median, Turkish,...
The Romans had a very standardized way of building their fortifications. Archeologists can look at photographs of most sites and tell who build them by the style and layout
Rome had a standard template on what a fortification layout looked like.
A Roman soldier could go from any Roman fort to any other Roman fort and instantly know where everything in that fort was located.
Sorta important when you need to respond quickly to any attack, be it barbarians or diarrhea...