My "take" ...
"Church" means "the gathering." The term refers to the community, communion, fellowship, "oikos" of Christians... it is PEOPLE, people united by the divine gift of faith; it's a corporate reality of faith - people with faith. The Bible speaks of it as such...the Nicene Creed speaks of it as such. But the term ALSO came to mean a local gathering of Christians (and seekers) in a given local and time, the church "at" a given place and at a given time (the church at Ephesus for example); in theology these are often referred to as "congregations" or "parishes" to avoid confusion with "church." Not for centuries was the term used for denominations (legal/economic/political corporations of congregations).
Christianity began more as a movement than anything, and well within Judaism. I think that's how early Christians understood themselves, rather like "fulfilled Jews." Judaism was already a diverse group and had a history of being with little organization (until the Romans legalized it). But the division happened fast! We already see in the New Testament itself (especially in Acts) this separation happening as Christians begin to worship separately and undergo persecution from Jews. Soon, believers became known as Christians, not Jews. Christians, Jews, Romans, the culture - all soon came to understand Christianity as a distinct religion/community.
But for 300 years (a long time!), Christianity was an illegal religion often undergoing persecution - from the Jews, from the Romans, from the general culture. It was often an "underground" religion, meeting in small groups often secretly and in private homes or secret locations. There was no central ANYTHING and it was VERY diverse. Perhaps at no time in the 2000 year history of Christianity was it more diverse than in these early years (well, today might be just as much so!). Theology was pretty much all over the map... even the very esteemed "Fathers" often varied greatly in their beliefs and debated strongly with each other, already there was developing "East vs West" theologies and practices. There were no "church councils" because there was no agency to call such and no ability to standardize any opinions of such. But there DOES seem to be a growing consensus - however informal - and we see this in the rejection of Gnosticism, the growing embrace of 27 Christian Scripture Books, the growing embrace of certain "fathers" as opposed to some others... it was informal, it was unofficial, it was far from perfect, but there was a growing popular consensus WITHOUT any Body or individual or denomination - just Christians in general embracing some things, rejecting some things, and letting many things be said or done without affirmation or condemnation. All very informal, unofficial.... just Christians evolving. NOTE: There was NO denomination during this time, no central anything, no legal/political corporation of congregations. It was a movement, little more than a loose, informal, unofficial entity of thousands of congregations (most tiny and unorganized.) Since Christianity was illegal, it's understandable that Christians avoided headquarters and lists and centrality.
A radical change happened in the early Fourth Century when the Empire first legalized Christianity and then made it the State Religion. Suddenly, in one bold swift political move, Christianity was a ROMAN thing, the church a ROMAN and POLITICAL institution, an agency of the Empire (just like the military). IMO, this huge event was a real "mixed blessing" but that's another topic, the reality is: For the Roman Empire anyway (not outside it, we are NOT talking anything universal or impacting all Christian people or Christian congregations!), the church was an political thing, an agency of the Roman Empire, at least sort of under the control of the Emperor. And Rome was OBSESSED with power, control, and lording it over people (Matthew 20:26). And predictably, formed the church in its own image - very much from the top down, like the Roman army, like Roman government, like Roman business. Now, we have a denomination - a political, economic, legal corporation intend on control. We have a body of all congregations within the Empire. Now, we have what might be called "The Church of the Roman Empire" - although it often referred to itself as "catholic" (universal - over the whole Empire) or "orthodox" (true, correct, authentic) but these were adjectives, not proper nouns. This ORGANIZATION was imposed throughout the Empire by the Emperor but it proved unequal - it was more "Roman" in the West than in the East where control and centralization was less embraced and a more collegial, informal and less defining approach was seen (truth: Eastern and Western Christianity never united but continued to grow apart, even under Roman control).
Was this The Roman Catholic Church? Can we say what the Roman Empire first created in 311 was THE Roman Catholic Church? That's very difficult to say.... it included nothing outside the bounds of the Empire.... it was both East and West... not one of the distinctive teachings of the RCC was taught by this Roman agency... there was NOTHING distinctively RCC about this Roman agency. But it can be said that the RCC (and EOC) and actually EVERY Western denomination can be historically TRACED BACK to this Roman denomination (in much the same way as nearly every Western country can be traced back to the Roman Empire, but it's foolish to say the USA was founded in 753 BC because Rome was). Nearly every denomination can trace itself back to this denomination Rome created... but that doesn't make it The Roman Church.
Christianity can be said to have been founded by Jesus and the Apostles.... but not any particular congregation or denomination. Indeed, we see nothing that can even be thought of as an institutional organization of all Christianity - even though Rome tried to do that in 311 (it fell apart soon thereafter) but even then, only for itself.
Now, the LDS and RCC and a few other denominations and cults can claim big, egotistical, self-serving things to try to justify lording it over others as the Gentiles do, to justify the power-grabbing demands of itself, to evade accountability, but sorry - neither history or Scripture supports such. Sorry. That's the reality.
I have nothing per se against denominations, but the claim that Jesus or Peter founded one is, well, absurd... and there's no evidence that any (including The Catholic Church) existed prior to Rome's creation in the early 4th Century. Sorry. Just the reality.
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