One does not divide the Church, one leaves it, generally through heresy and apostacy.
The Church is found where ever we find Spirit filled believers who walk in the Word of God. We find also those in the Church who are ill and feeble with arrogance and can not walk in Truth, for they have rejected it. Yet, they all are a part of the Church. For all have believed in Jesus Christ as Savior.
Matthew 18:20 (New International Version)
"For where two or three come together in my name, there am I with them."
As for the
first Church? It was to be found in Jerusalem. Not, Rome. If anything, Rome broke off from the true Church, if true churches are to be based upon who came first.
And? The creeds of this first Church? These are to be found in the source of all true creeds. The Bible.
1 Corinthians 11:18-19 (New International Version)
"In the first place, I hear that when you come together as a church, there are divisions among you, and to some extent I believe it. No doubt there have to be differences among you to show which of you have God's approval."
According to the Apostle Paul, not everyone in the Church desires the Truth. Yet, he never says they are not of the Church. And, he said that there will be divisions in the Church because volition is the determining factor in securing God's approval.
John 4:23 niv
"Yet a time is coming and has now come when the true worshipers will worship the Father in spirit and truth, for they are the kind of worshipers the Father seeks."
The approved ones in the Church will worship the Father in the filling of the Spirit and the accepting of the Truth of God's Word! Not, the teachings and traditions of men!
John 17:17 niv
"Sanctify them by the truth; your Word is truth."
The first days of the Church were the most dangerous times for apostasy. For Satan and his demons only had a small group of believers to concentrate all their evil energy upon! To think that the first days of the Church were free of error is not good thinking!
2 Peter 2:1 niv
"But there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the sovereign Lord who bought thembringing swift destruction on themselves."
The early Church was under the most concentrated attack at that time! False teachings were bound to creep in. The only safety the Church had was to be found in Scripture! It was conspiratorial in manner as false teachings were entered. It was done in secret.
If one had no first hand knowledge of Scripture (as many Gentile believers did not) then such false ideas and beliefs were slowly introduced over time, unchallenged. A new religion in the name of Christ was slowly replacing the spiritual way of life to be lived in the Spirit, instead of seeking truth to become transformed by in the power of the Spirit. Teachings of men were being introduced to induce a religious conformity in the power of the obedience of the flesh. "Religion."
2 Corinthians 11:12-14 (New International Version)
"And I will keep on doing what I am doing in order to cut the ground from under those who want an opportunity to be considered equal with us in the things they boast about. For such men are false apostles, deceitful workmen, masquerading as apostles of Christ. And no wonder, for Satan himself masquerades as an angel of light."
Devious men who came in the name of Christ were bound to find ways into obtaining power as long as men remained ignorant of what Scripture said on a matter..
Only
the Word alone protects the Spirit filled believer from such men. Others who seek unity for
the glory of unity, will accept obediently things that sound good and appeal to their natural way of thinking.
That is how we see the ascendancy of the traditions of men taking over the Church. The Reformation was God's answer to this ever growing conspiracy over his Church. And, even the Reformation was not without its problems = ignorance of other truth which was now to be needed to continue to grow in Christ.
And, there can be no unity of all believers until the LORD returns. For now on earth is the time that God tests men's hearts to see who it is he approves of for His next advancement into great rewards and honor in the next life.
No doubt there have to be differences among you to show which of you have God's approval."
Not all who are in the Church will receive great rewards and Eternal blessings simply because they are saved!
One can now be 100% loyal to the traditions set forth by religious men, and be without any reward when they are evaluated by the LORD of Glory in heaven. Wood, hay, and staw.
1 Corinthians 3:12-15 (New International Version)
"If any man builds on this foundation using gold, silver, costly stones, wood, hay or straw, his work will be shown for what it is, because the Day will bring it to light. It will be revealed with fire, and the fire will test the quality of each man's work. If what he has built survives, he will receive his reward.
If it is burned up, he will suffer loss; he himself will be saved, but only as one escaping through the flames."
We can not lose our salvation. But, we can lose out on the great opportunity our salvation time on earth now offers for us. Which is, to walk in the power of God's grace and truth. Religion is law and order for the flesh to conform to. Religion gives immediate feedback that our human reasoning can find merit in. This makes men proud (in a humble appearing way) of what they believe in. Muslim, or some Christian religion, makes no difference. Only those who walk in Spirit and Truth will understand. Not all believers choose to.
Some are here to compete against others. Their church against your's. Others, are here to make us think. They are not the same things.
God does not compete. He reasons. God is not out to impress others with an image of one's presentation. He is out to make known what it is we need to know in order for the Holy Spirit to bring us one step closer in knowing more of what is contained in the mind of Christ!
Religion is an established order for the flesh, so it can feel justified in its arrogance.
Religion = pride protected in the name of God. It has the appearance of humility, if that is what is called for. It works at being humble in appearance.
Life in Christ = the revelation of Truth in our soul that changes us and transforms our very expression into becoming an ambassador for Christ.....
There is no division in God. There is no division in those who walk in the power (grace) of the Holy Spirit. What may appear to be a division in truly Spirit filled believers is usually a matter of differences in maturity levels at the time they meet. Its the mature who will remain at peace within themselves as they see those following to where they have now find themselves.
Its those who cling tenaciously to religion that the mature in Christ have no sympathy for. These ones are recommended to go find another pew to sit in. One that they can agree with. For, there is no hope for the religious without God personally smashing their pride and causing them to realize their true helplessness. God must do it.
In the mean time, they should go find a place where they will be out of the way of those who do desire to grow in grace and truth. Therefore... God allows for many different types of Christian religions to exist for this purpose. They are called... denominations. One fights against the other. Playing spiritual king on the mountain = pride.
Religion competes and demands conformity to its ways. The other, reveals truth, and leaves them in the hands of the Spirit to break through to their hearts, if its to be done.
2 Timothy 4:3 (New International Version)
"For the time will come when men will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great number of teachers to say what their itching ears want to hear."
God allows for that diversity of choices away from the truth, so that those who do truly desire sound doctrine can sit in a pew and not have to have around them all the distractions that come from negative volition towards God's Word when taught soundly. To say that there are no churches that teach the Word of God accurately, is to also say there is no God.

Matthew 5:6
"Blessed are they which do hunger and thirst after righteousness: for they shall be filled."
Those who hunger after
self righteousness will seek out religion. A denomination that sets up walls as to box God's Word in. Those who hunger after righteousness, will seek out sound doctrine.
So be it.....