How about the (resurected) Roman Empire under Charlemagnes ?
You have very different cultures under one crown (French, German, Lombard), united for a short period of time by conquest, and the society is probably closer to that of the Old Anuirean Empire than the Roman society.
The (First) Roman Empire is probably the only time that you’ll see Western Europe (for Anuire) and the Middle East (for Khinasi) under one sovereign, but I think the society is just too different to fit well, there is nothing like the feodal organisation of the Old Anuirean Empire.
Canon-wise the Anuirean Empire would be more like Charlemagne’s, or the later Holy Roman Empire, than the Classical Roman one. It “appears” that Anuire has always been a feudal society. So the Classical Roman/Greek society seems to have never existed in Cerilia.
You are trying way too hard to find one perfect analog for all of the elements of Anuire.
Anuire is its own place. It has some similarities in some places to France, or a Rome +1000 years, Byzantium, the Holy Roman Empire, England. It is in some ways an amalgam of ideas from around Western Europe mixed with some original stuff and some fantasy.
There is no country with Anuire’s situation or history. The best you can do is draw analogies to elements of Anuire.