Even in the early days, as we find in the Book of Acts, there were splinter churches and dissenters. One of the marks of the true Church was that it was universal, not a dissident local church.
So when it came to defining the Church at the Council of Nicea, it was said to be One, Holy, Catholic, and Apostolic.
There is only one true Church. So it says in the Bible. That one true Church is also seen to be Apostolic, headed by the bishops who descend from the original Apostles in unbroken succession. Catholic Church simply means Universal Church.
That was one reason why I left the Anglican Church, because like Newman I concluded that there was no way that it could be the universal Church, throughout the world and through all time since its founding by Christ. I received great good from growing up in the Anglican Church. I have read and considered its own claims to be universal and apostolic, and I found that I simply could not justify those claims.
The Council of Nicea put the word Catholic into the creed, but of course, as this article suggests, the word can be found much earlier, as a response to splinter groups that go back to the earliest days when the original apostles were still active.
Cicero wrote:
That was one reason why I left the Anglican Church, because like Newman I concluded that there was no way that it could be the universal Church, throughout the world and through all time since its founding by Christ. I received great good from growing up in the Anglican Church. I have read and considered its own claims to be universal and apostolic, and I found that I simply could not justify those claims.
Well said.