Are you saying that back then they were much more diverse than say the 33,000+ Protestant denominations that exist today? What proof do you have? That is like saying every Christian in the Early Church had his own personal Church and was his own personal church leader with his own personal deposit of faith.
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Yes they were MORE diverse in many respects. Those first believers were Jews…who continued to worship as Jews…at this time in Judaism there were competing sects claiming to be…or wanting to be the “authorative” version and expression of Judaisim. Pharisees, Sadduceees, Essenes…to name a few we are familiar with…into this “mileu” came followers of Jesus of Nazareth…claiming to be “authentic Israel” rightful legacy…They were distinctively Jewish…and continued to preach circumcision…until Paul the “Christian movement” stayed a “Jewish phenomanon” and not terribly significant.
Once Paul’s vision of his type of Christianity took hold…Christianity began a population exposion. One of the things that prohibbited the “God fearers”, Gentile believers in the God of Israel, from becoming FULL JEWS…was the rite of circumcision…a painful and dangerous procedure for adult men…when in Christianity one also got the “God of Israel” and NO CIRCUMCISION…once the Fall of Jerusalem the competition for “authenitic Judaism” was between the Pharisee Rabbinic Movement and the followers of Jesus of Nazareth.
As more and more Gentile entered the Church…the church in isolated locations “drifted” far from it’s Jewish roots…out of this time came the Synoptic gospels…I’m of the opinion that the gospels were written by “God-fearer” converts who didn’t fully understand the Hebrew scriptures…which is why we find so many miquotes in the gospels from the prophets…Christianity had become more Gentile than Jewish.
Some isolated groups had very “similar” beleifs…but different still. Early Christianity was more about Jesus words and how to live in this world than it was about rites and rituals that needed to be performed…Christianity ‘re-emerged’ in the 2nd century now established in various “schools” of thought…“proto-orthodox/catholic”…Arian…Gnostic…Ebionite…Manichee was quite sucessful in Asia Minor…in some places the Manichess we the ONLY version of Christianity there was…and while some of the groups which existed were quite small…but their belief are addressed in writing such as “Gospel of Peter”…“Gospel of Thomas”…even the “Gospel of John”…which was disputed for centuries …theology reflected it’s theology in it’s various “Johaninne communities”…and John’s gospel was used by some “orthodox” as well as “gnostic” groups.
Many of these groups had similar theology…but different enough that “inter-communion” between some of them could not take place…which we see finally defined in later years between some of the Orthodox groups…Coptic…Armenian…Ethiopic to name a few.
The “First Christians” we all about what Jesus taught and made their communities into reflections of his teachings…by the second century the focus had shifted from “what Jesus taught” but “who Jesus was”. It was during the 2nd century that some of the more “vocal” and prominent groups began to unify under recognized “bishops” and “schools of thought”… who eventually joined these congregations together under an hierarchal form of government and began it’s further definitions of fine parts of “theology”…the “heretical” teachings were defined and more so called “orthodox” belief took prominence…
This is a “shoestring” history on my part…but there are volumes and volumes of critical study on the Early Christian Church’s history published in the last few decades.
The struggle between the Pauline congregations and theology between the leadership of the Jerusalem church and James is one such view of diversity…even though the writer of Acts seeks to gloss over and give us “pious history” of those first decades.**

Truth > such ideas