I have a question about the DLC campaign. I decided to settle immediately. Conquered Vandals, Justinian is nowhere in sight, busy in Italia.

Now, the question is about the culture, buildings and diplomacy. I can build Roman barracks and recruit Roman units, but can only build wells and canals for sanitation. I captured a Vandal city, it had public baths and they were marked as the other culture building with a red triangle and it can't be upgraded. How can the Goths build such Roman buildings, and I can't?

Also, in the diplomacy screen, Visigoth, Ostrogoths and Sardinians are marked as Same people, with the wrestling hands icons. I thought Belisarius is a true Roman, and definitely not related to Goths.

So my question is, is my game working as intended (no mods loaded) or is it like written above by design?