Is it a coincidence that the current Eastern Orthodox nations are often in the same territory of the Eastern Roman Empire and later Byzantium?

[LegateLivius]

Found this thread earlier bak int he weekends.

https://www.reddit.com/r/ancientrome/comments/1bed6er/why_do_romance_languages_have_so_strong/

Be sure to read it because the OP is very necessary as context to this new question.

So while the correlation to Slavic languages and Greek is quite murky unlike Romance languages and the Western Roman Empire in tandem with Catholicism....... Am I alone in seeing that so much of modern Eastern Orthodoxy today is in the former Eastern half of the Roman Empire and the later Byzantine empire? Is it mere coincidence or is there actually a direct connection?

I mean even countries that were never Eastern Orthodox during the time of the Roman Empire often had strong trading connections with the Eastern half as seen with Russia's history.

So how valid is this observation of mine?

[caldrail]

"Byzantine "Empire" is the modern name for the Eastern Roman Empire, and back in Medieval times, they were known as Romans. The schism between the Catholics and the Greek Orthodox chuches is well known, so the observation is basically valid.