In 325 AD the Christian Church was about 300 years old and was “one holy, catholic, and apostolic church” meaning that it was established by Jesus, God in flesh, was universal, and was led by bishops of the time, successors of the original apostles who were followers of Jesus during his earthly ministry
Decades of study and discussion had resulted in general agreement on documents to be included in the Christian Holy Bible, but it would be another 42 years before the earliest extant publication of the list of 27 books comprising the New Testament taught by Christian Churches today.
In 325 AD, the first split in the “one holy, catholic, and apostolic” Christian Church, Eastern Orthodox vs. Western Roman Catholic in 1054 AD, was 729 years in the future, and the Protestant Reformation, which ignited unending splintering of the Church, was 1192 years in the future.
The battle for truth in Christian theology has been long and troublesome. Even in the first century, Jesus and his followers were often challenged by false teachers and false teachings. The New Testament includes mention of the antichrist denying that Jesus was divine, a different gospel, false doctrines, corrupt minds, and depraved conduct.
The battle for truth wasn’t any easier for the successors of the original apostles who were constantly fighting heresies. The church teachings were challenged in the first 300 years by Gnosticism, Docetism, Arianism, Monarchianism, Adoptionism, Marcionism, Montanism, Ebionitism, Macedonianism, and Novationism. A typical theme of the heresies was denial of the Trinity, God as Father, Son, and Holy Spirit, a treasured belief of essentially all Christian churches today.
The Nicene Creed which originated in the First Ecumenical Council of the Christian church in 325 AD addressed Arianism, a heresy mentioned in the previous paragraph. Arianism challenged the divinity of Jesus and of The Holy Spirit. Hundreds of bishops met in Nicaea to clarify the truth about the divinity of Jesus. Thanks to Newadvent.org we have an English translation of that first Nicene Creed. The original language was Greek.
We believe in one God, the Father Almighty, maker of all things visible and invisible; and in one Lord Jesus Christ, the Son of God, the only-begotten of his Father, of the substance of the Father, God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father. By whom all things were made, both which be in heaven and in earth. Who for us men and for our salvation came down [from heaven] and was incarnate and was made man. He suffered and the third day he rose again, and ascended into heaven. And he shall come again to judge both the quick and the dead. And in the Holy Ghost. And whosoever shall say that there was a time when the Son of God was not, or that before he was begotten he was not, or that he was made of things that were not, or that he is of a different substance or essence from the Father or that he is a creature, or subject to change or conversion — all that so say, the Catholic and Apostolic Church anathematizes them.
Fifty-six years later in the 381AD First Council of Constantinople, the bishops addressed Macedonianism which denied the divinity of The Holy Spirit. They added the phrase, “And in the Holy Ghost, the Lord and Giver of Life; who proceeds from the Father; who with the Father and the Son together is worshipped and glorified; who spoke by the prophets.”
It was another 208 years until, at a Council of Toledo, the Latin church unilaterally added the Filioque phrase, “and the son,” to the Holy Spirit phrase making it “And in the Holy Ghost, the Lord and Giver of Life; who proceeds from the Father and the Son; who with the Father and the Son together is worshipped and glorified; who spoke by the prophets. What a shame that the Filioque was a contributing factor motivating that first 1054 AD split in the one holy, catholic, and apostolic church.
One thing we might take away from this narrative is that all Christian churches owe thanks to the universal Church of those early centuries for defining the contents of our New Testament and for clarifying our fundamental theology about the Trinity.
Another thing we might take away from this story is that when it comes to its responsibility for truth on theological issues, the Catholic Church is slow and deliberate.
Below is the 2025 Nicene Creed, the English version approved by the US Conference of Catholic Bishops following Vatican II (1962-1965), the 21st Ecumenical Council of the Catholic Church. If curious about those 21 councils, go to magisterium.com and ask for a list of the ecumenical councils of the Catholic Church. It is interesting.
The Nicene Creed
I believe in one God,
the Father almighty,
maker of heaven and earth,
of all things visible and invisible.
I believe in one Lord Jesus Christ,
the Only Begotten Son of God,
born of the Father before all ages.
God from God, Light from Light,
true God from true God,
begotten, not made, consubstantial with the Father;
through him all things were made.
For us men and for our salvation
he came down from heaven,
and by the Holy Spirit was incarnate of the Virgin Mary,
and became man.
For our sake he was crucified under Pontius Pilate,
he suffered death and was buried,
and rose again on the third day
in accordance with the Scriptures.
He ascended into heaven
and is seated at the right hand of the Father.
He will come again in glory
to judge the living and the dead
and his kingdom will have no end.
I believe in the Holy Spirit, the Lord, the giver of life,
who proceeds from the Father and the Son,
who with the Father and the Son is adored and glorified,
who has spoken through the prophets.
I believe in one, holy, catholic and apostolic Church.
I confess one Baptism for the forgiveness of sins
and I look forward to the resurrection of the dead
and the life of the world to come.
Amen.