Wow, I learn something here. I always assumed the achievement required to reform the Roman Empire by decision. The phrasing is a bit strange. My bad for answering about a country I always refused to play.
The phrasing is inconsistent because the Basileus achievement was in patch 1.1 before the "Reform the Roman Empire" decision even existed. It made sense at the time as there was no other meaning. They never bothered to change the achievement wording after allowing the player to "Reform the Roman Empire" in Mare Nostrum.
The images matches though, as far as I can see. Do you lack any of the tiny islands (like Corfu) that are hidden behind the government tab in the screenshot?
Yeah, the images are pretty close, Corfu and the stuff on the Eastern Adriatic are the only provinces you can't really see. I can't tell if the map on the wiki is up to date regarding provinces changes either. If not, OP might need a few more around the edges.
it's not forming the really big roman empire, as all my friends have done it without doing that unless its changed, i have waited about 2 years, here's the what provinces i need, pretty sure i have all of them unless I'm being blind
Click on the Achievement (Trophy) icon, scroll down to the achievement and see if it has a red cross or a green check. If you hover over it, it will list the total number of requirements and which ones you've completed. Hopefully you'll see most/all of the list, but sometimes there will just be the number to let you know how many provinces you still need.
Did any of these provinces change in CoC? If so, it's entirely possible the achievement is bugged. That can happen if province ids get changed/added or areas altered.