Historical Development of the Trinity doctrine in the first centuries

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Nicene Creed
Emperor standing behind the church fathers

The church adopted the Trinity doctrine at the conclusion of the fourth-century ‘Arian’ Controversy. However, over the past 100 years, scholars discovered that the traditional account of how and why the church accepted that doctrine is grossly inaccurate. The purpose of this article series is to explain the true origin of the Trinity doctrine. This series emphasizes the fourth century, but it is also important to consider the views of the pre-Nicene church fathers and key events in the fifth and later centuries that established the Trinity doctrine in the church.

This first article:

    • Discusses the different views of God and
    • Explains the conceptual and historical development of the Trinity Doctrine.


One Definition

Matt Slick, a prominent Trinitarian apologist, defined the Trinity, in summary, as follows:

God is one, but is a Trinity of three distinct persons; the Father, the Son, and the Holy Spirit.

Each has a will and is self-aware, but they are not three beings. They consist of one substance.

Each person is the one God and is eternal, equal to the others and equally powerful.  

Jesus, as a man, has both a divine and human nature.

Arian or Sabellian Controversy?


It would be much more appropriate to call it the Sabellian Controversy:

The Nicene Council was forced to accept the term homoousios because Emperor Constantine supported the Sabellians and because the Sabellians preferred the term. (See here) For example:

        • “Simonetti estimates (that) … Alexander … accepted virtual Sabellianism in order to ensure the defeat of Arianism.” (Hanson, p. 171)
        • “N [the Nicene Creed] appeared to favour the near-Sabellianism of Marcellus.” (Hanson, p. 272)

In the decade after Nicaea, the church corrected the distortion caused at Nicaea by exiling all leading Sabellians. (See here)

In the 340’s the Western church supported a Sabellian (one mind) theology. (See here) For example, Hanson refers to the Western bishops’ “traditional Monarchianism.” (Hanson, p. 272)

Athanasius was extremely influential in the West and also had a ‘one hypostasis’ (meaning one Person with one mind) theology. (See here) For example, “In the Father we have the Son: this is a summary of Athanasius’ theology.” (Hanson, p. 426)

The key focus of the anti-Nicenes, also called the Eusebians, was to oppose Sabellianism. For example:

“More recent and more thorough examination of Arianism has brought a more realistic estimate of it. Simonetti sees it as an extreme reaction against a Sabellianism which was at the time rife in the East.” (Hanson, p. 95)

Referring to the Dedication creed, Hanson says: “Its chief bête noire is Sabellianism, the denial of a distinction between the three within the Godhead.” (Hanson, p. 287)

One Substance

Slick also says “They consist of one substance.”

In Slick’s definition, “each person is the one God.” In other words:

God = the Father = the Son = the Holy Spirit

This sounds like Modalism, where the Father, Son, and Holy Spirit are not three different Persons, but three modes of the same Person. But then Slick adds that they are “three distinct persons.”

In Slick’s definition:

The three-ness of God is expressed as three separate wills and minds.

The one-ness of God is expressed as a single substance, understood as a single Being.

Historical and Conceptual Development

The Trinity doctrine has been developed over about 400 years:

The early parts of the New Testament, such as the Gospel of Mark present Jesus mostly as simply an inspired man to whom God granted authority to forgive sins and authority over nature.

The later parts of the Scriptures, such as the writings of Paul and John, have a much higher Christology, listing many of His divine attributes, but also maintain a distinction between God and Jesus and present Jesus as subordinate to God.

Before Christianity was legalized in the year 313, different theologians proposed different theories attempting to explain the relationship between God and Jesus. However, Christian were more concerned about staying alive than to have a uniform understanding

the church simply The conceptual progression and historical development of the Trinity theory can be described as follows:

Jesus is God.

Worship JesusBased on the High Christological statements in the Bible, Trinitarians believe that Jesus is God as much as the Father is God. This was the main point of the Nicene Creed of the year 325, which identified the Son as “true God from true God.”

One Being

This Nicene Creed caused much dispute and controversy in the church for the next 50 years, for the Bible is clear that only one God exists (monotheism). Trinitarians, therefore, developed the concept that the Father, the Son, and the Holy Spirit are a single Being; that together they are the one God of the Bible.

Three Persons

However, since there are differences between the Father, the Son and the Holy Spirit, such as that the one is begotten and the other not, the thought developed that they are three different Persons within the one single Being. This concept was reflected in the writings of the Cappadocian Fathers, late in the fourth century.

The word Trinity has two possible meanings. With a lower case, “trinity” simply means a group of three. Some early Christians used the word in that sense. They did not yet differentiate between upper case and lower case letters, but that was the meaning they attached to the Greek and Latin equivalents of the word. But, today, we do differentiate between upper and lower case, and we use the word “Trinity,” with a capital “T,” as a proper name for the single Being who consists of three divine Persons.

Two Natures

But then, Christ Jesus, when He was on earth, did not know the day and hour of His return, and said that only the Father knows that (Matt 24:36). And, in many other ways, He indicated that He is subordinate to the Father. For example, He was sent by the Father and the Father gave Him what to say and what to do. 

Trinitarians, therefore, developed the thought that Jesus had both a human and a divine nature. In His human nature, He did not know the day or die hour, but in His divine nature, He knows all things. This “two natures” theory was formulated at the Council of Chalcedon in the year 451.

The foundation on which the Trinity theory rests is, therefore, the conclusion that the Son is God as much as the Father is God is. The other aspects of the doctrine, namely that God is one Being but three Persons, and the theory that Jesus has two natures, are attempts to reconcile the Bible with the conclusion that the Son is God. 

The concepts in this section will be brought out in more clarity in the articles that will follow.




The foundation on which the Trinity doctrine rests is that Jesus is God as much as the Father is God.

To reconcile this with the monotheism of the Bible, namely, that we only have one God, the next step was to argue that the Father, the Son, and the Holy Spirit are a one single Being.

But since there are many obvious differences between them, such as that the Son prayed to the Father, the thought was added that they are three different Persons within one single Being.

However, Jesus said and His disciples believed that He is subordinate to the Father. He said, for example, that of the “day and hour” of His return “no one knows, not even the angels of heaven, nor the Son, but the Father alone” (Matt 24:36). And Paul referred to “God” as “the head of Christ” (1 Cor 11:3). To address this challenge, the church developed the theory that Jesus had both a human and a divine nature. In His human nature, He is limited and only on earth, but in His divine nature, He is omniscient and omnipresent. In other word, He said in His human nature that He does not know but in His divine nature, He knew all things.

These formulations of the relationship between the Father, Son and Holy Spirit were developed over a period of about 400 years.


In the year 325, the Council of Nicaea concluded that the Lord Jesus Christ has the same substance as the Father (homoousios) and is co-equal with the Father. The purpose of the first articles is to determine what Christians believed about Christ and the Trinity in the three centuries before Nicaea.


Matt Slick is a prominent Trinitarian apologist.  To prove that Christians did believe in the Trinity during the first three centuries, his brief post, “Early Trinitarian Quotes,” provides a collection of proof-texts from prominent second and third centuries theologians.

Sean Finnegan—a Unitarian (believing that the Father alone is God)—responded to Slick’s article with an article titled Trinity before Nicaea.  His purpose was to show that Christians in the first three centuries did not believe in the Trinity. He discussed Slick’s articles but added further quotes. Dr. Tuggy’s podcast 262 presents his response. Dr. Tuggy is a well know Socinian Unitarian, which means that he believes that Christ did not exist before His human birth.  

The current article series analyzes the quotes from both these articles to determine what the Christian authors believed in the first three centuries about the Father, the Son, and the Holy Spirit. The purpose is not to determine whether those early Christians were correct in what they taught, but, rather, to understand whether the Nicene and later creeds were consistent with the teachings of the early Christians.

To simplify these articles, many of the quotes below are summarized.  For the full quotes, refer to Finnegan’s article.



AriusIn the fifty years after Nicaea, The Nicene Creed was generally rejected by the church. Several other views were proposed. One of these views is the view as reflected by the Nicene Creed, but other views include that the Son  and various other creeds were developed during those years in an attempt to find the right answer. In all of these views, the 

to Arianism was the main competitor for the Trinity theory and dominated the church until the year 380. Arianism is explained in a later article.  In summary, Arianism argues that the Son is not equal to the Father, but was begotten by the Father before time and that God created all things through the Son.  In other words, in the infinity beyond time, the Father was before the Son, but then we use the word “before” metaphorically. 


The articles below discuss the Christologies of Polycarp, Justin Martyr, Ignatius of Antioch, Irenaeus (bishop of Lyons), Tertullian and Origen. Origen was the greatest and most influential Christian theologian before Augustine. The purpose is to evaluate the following aspects from the definition of the Trinity against their works:

1. The Son is God.
2. The three Persons are equal.
3. The Holy Spirit is self-aware.
4. The three Persons consist of one substance.
5. Jesus has both a divine and a human nature.

List of all articles on this website