I'm rather surprised that no-one has mentioned the Eastern church, In the first few centuries most christians lived in west Asia. And, probably missionaries of that early church had preached their message all the way across Asia even as far as China. Just because we live in a world where the ROMAN church has been the dominant force in the Eurocentric world, doesn't mean that was always the case.
Let's think about the 'church' as it was in the first century. Undoubtedly, it was controlled by James and his family, at least until the Roman's destroyed Jerusalem and excluded ALL Jews from the city, The best descriptive term to describe that early group of believers is this - "the early church.'
So when did it become the "Roman Catholic Church?" It's difficult to fix a specific date, and I suggest that it was a gradual process, but certainly by the time of Constantine we could define it with that specific term. The only problem we have then, is that Constantine moved the capital of the political empire to the new capital of Constantinople - also known as Byzantium (now an Islamic city named Istanbul).
There is every reason to believe that the religious power of the church became centered in Constantinople also, as nearly all emperors after Constantine were christian (I can only think of Julian the Apostate as the only non-christian emperor) and issued religio-political edicts governing the lives of Roman citizens throughout both the eastern and western sections of the empire.
The western section of the empire was increasingly unimportant until the barbarians conquered Rome and we see a divide between the barbarian controlled Europe and the Graeco-Roman eastern section now generally known as the Byzantine Empire.
As I'm sure you guys will be aware, Constantinople survived as a Christian centre for centuries even surviving the horrifying sacking of the city by the European christian crusaders, Only the the Islamic tsunami ended Constantinople's christian heritage, and contrary to the opinion of many, christians were treated better by their muslim conquerers than their ancestors had been by the christian crusaders of the fourth crusade in 1204, who had looted the city's treasures and raped the women of the city(including nuns).
Would you not think that logically, Orthodox Christianity should be seen as the rightful lineage?
Not that I care in a spiritual sense> A plague on ALL these religious pests!