When the Dacians reappeared, what happened on the faction strength graph?? Did they have a gap in their graph, or start again????

In MTW the reappearances seemed to be anywhere where they had controlled territory. I tried not to think about them as countries, but as feudal dynasties which did end up all over the place (say Angevin Hungary)... so it didn't bug me much.

In RTW times tribes/people moved/were moved around a lot so reappearances all over the place would not be an issue, in fact are quite explicable, in my opinion.