Basil of Caesarea taught three divine Beings.

Summary

Basil of Caesarea was the first of the Cappadocian fathers and made a very important contribution to the development of Nicene theology.

In the Trinity doctrine, God is one Being with a single mind, existing as three Persons. It is often claimed that that is what Basil taught, but this article shows that Basil taught that the three Persons are three distinct Beings with three distinct minds.

That is also what the so-called Arians taught. However, while the Arians taught that the Son and Spirit are ontologically subordinate to the Father, what made Basil unique is that he believed that the Persons are ontologically the same. The Nicenes before Basil also believed that the Son is ontologically subordinate to the Father. They said that the Son is part of the Father, implying ontological subordination.

Although Basil taught that the Son and Spirit are ontologically equal to the Father (the same substance exactly), he preserved a certain order among the Persons. He refused to say that the Spirit is homoousios. He never described the Spirit as God, but described the Spirit as third in order and dignity. He believed that the Father alone exists without cause and maintained the priority of the Father.

This article elaborates on the following indications that Basil regarded the three Persons to be three distinct Beings:

1. Basil began as a Homoi-ousian, who believed in three distinct Beings. 

2. For Basil, homoousios meant that the Son’s substance is like the Father’s, implying distinct substances.

3. Basil said that homoousios corrects Sabellianism, for it keeps the Persons distinct.

4. For Basil, the Persons are instances of divinity just like people are instances of humanity.

5. Basil described the Father and Son as having distinct minds and wills, implying distinct Beings.

6. Since he maintained a hierarchy between the three Persons, it is difficult to imagine that Basil believed them to be one single Being.


Introduction

The Traditional Account

Due to research and a store of ancient documents that have become available over the last 100 years, scholars today conclude that the traditional account of the Arian Controversy – of how and why the church accepted the Trinity doctrine – is history written by the winner and fundamentally flawed.

The “conventional account of the Controversy, which stems originally from the version given of it by the victorious party, is now recognised by a large number of scholars to be a complete travesty” (Hanson).

“The diatribes of Gwatkin and of Harnack (published around the year 1900) can today be completely ignored” (Hanson, p. 95).

Books Quoted

Only a handful of full-scale books on the fourth-century Arian Controversy have been published since Gwatkin’s book at the beginning of the 20th century. This article series is based on books by world-class Trinitarian scholars of the last 50 years:

Hanson, R.P.C. (Bishop) – The Search for the Christian Doctrine of God – The Arian Controversy 318-381 (1987)

Williams, Rowan (Archbishop) – Arius, Heresy & Tradition, (2002/1987)

Ayres, Lewis (Professor of Catholic and Historical Theology) – Nicaea and its legacy, An Approach to Fourth-Century Trinitarian Theology (2004)

Anatolios, Khaled – Retrieving Nicaea (2011)

Basil of Caesarea

Basil became a bishop in 370. He made an important contribution to the development of the Trinity doctrine:

The three ‘Cappadocian theologians’, Basil of Caesarea, Gregory of Nazianzus, and Gregory of Nyssa “were together decisively influential in bringing about the final form of the doctrine of the Trinity” (Hanson, p. 676). Show More

Hypostasis and Ousia

Since these terms are important in this article, it is appropriate to begin with a brief overview of these terms:

The Trinity doctrine defines God as one Being (one ousia)  existing as three Persons (hypostases) (see here for a detailed discussion). In other words, it uses the terms ousia and hypostasis with opposing meanings.

In contrast, in the fourth-century Controversy, most people used the Greek words ousia and hypostasis as synonyms:

“For many people at the beginning of the fourth century the word hypostasis and the word ousia had pretty well the same meaning” (Hanson, p. 181).

Importantly, Athanasius, the paragon of the West, also used these terms as synonyms:

“Clearly for him hypostasis and ousia were still synonymous” (Hanson, 440). 

Both hypostasis and ousia meant an “individual existence” (Hanson, p. 193), “distinct existences” (Litfin), or “concrete individuals” (Anatolios, xiii). Show More

However, this article will show that, particularly following Basil of Caesarea, a distinction was later made between the meanings of the two terms.

Purpose

The purpose of this article is to show that Basil taught that the Father, Son, and Spirit are three distinct Beings with three distinct minds. This would be different from the Trinity doctrine, which defines the Father, Son, and Spirit as a single BeingBasil’s view may be compared to some other views during the fourth century:

Sabellianism

Sabellianism was still a strong force in the fourth century. The Sabellians believed that the Father, Son, and Spirit are a single Being with a single mind. The Sabellian minority at Nicaea supported the term homoousios and understood it to mean ‘one substance.’ In their view, the Son emerges from the Father merely as an energy. For example:

“Marcellus of Ancyra uses the language of ἐνέργεια (energy) to explain how it is that the Son can come forth and work without God being extended materially” (Ayres, p. 197). 

See here for a discussion of Sabellian theology.

Arianism

The Arians taught that the Father, Son, and Spirit are three distinct Beings with three distinct minds. For example:

Commenting on the Arian (Eastern) Dedication Creed of 341: “The bishops of Antioch … [were] insisting that Father, Son, and Spirit are three hypostaseis” (Anatolios, p. 24).

“Asterius (an early leading Eusebian) insists also that Father, Son, and Spirit are three hypostases” (Ayres, p. 54)

Since, at the time, the terms Being (ousia) and Person (hypostasis) were synonyms, when the Arians said “three hypostases,” they meant three Persons or Beings.

The Arians had accepted the term homoousios at Nicaea based on Emperor Constantine’s very vague explanation of the term. He said that it must not be interpreted literally, as if God is a substance, but that it only means that the Son is truly from the Father (see here). Show More

Nicenes

The Nicene theologians before the time of the Cappadocians, such as Alexander and Athanasius of Alexandria, like the Sabellians, understood the Father, Son, and Spirit to be a single Being with a single mind. They said that the Father, Son, and Spirit are a single hypostasis, meaning a single Person or Being. Show More

See here for a discussion of Nicene theology. The reader might expect to read here that the Nicenes said that God is one Being (one ousia) but three Persons (three hypostases). However, that concept did not yet exist. Alexander and Athanasius taught that the Father and Son are a single Person (hypostasis).


Ontological Equality

Basil was the first to teach ontological equality. 

When the Controversy began, all theologians regarded the Son as subordinate to the Father:

“With the exception of Athanasius virtually every theologian, East and West, accepted some form of subordinationism at least up to the year 355; subordinationism might indeed, until the denouement (end) of the controversy, have been described as accepted orthodoxy” (Hanson, p. xix).

Even Athanasius, the great defender of Nicaea, thought of the Son as subordinate in some ways. In the Nicene view, the Son is part of the Father, and, therefore, ontologically subordinate to the Father. Show More

Basil was the first to propose that the Father and Son are ontologically equal:

“In all the previous discussions (before Basil) of the term (homoousios) … a certain ontological subordination is at least implied” (Ayres, p. 206).

“In Basil, the Father’s sharing of his being involves the generation of one identical in substance and power” (Ayres, p. 207).

The next section will show that Basil, like the Eusebians (Arians), taught three hypostases. However, what made Basil different is that he believed that the Father, Son, and Spirit are “identical in substance and power.”


Three Distinct Beings

In Trinitarian theology, the three Persons are a single Being. Basil’s theology is often stated in ways that sound as if he also believed in only a single undivided substance (Being). But this section shows that he believed that the Father, Son, and Spirit are three distinct substances (three distinct Beings):

A Homoiousian

Basil began as a Homoi-ousian, who believed in three distinct Beings. 

Basil did not begin his career as a pro-Nicene. He began as an ‘Arian’; specifically, a Homoi-ousian, and gradually moved towards pro-Nicene theology:

“Basil emerged from a background, not of the strongly pro-Nicene theology of Athanasius, but of the school of Basil of Ancyra” (Hanson, p. 693).

“He came from what might be called an ‘Homoiousian’ background” (Hanson, p. 699)Show More

The Homoiousians were one of the Arian groups, and, as shown above, the Arians believed that the Son is a distinct divine Being. As a Homoi-ousian, Basil at first believed that the Son’s substance is similar to the Father’s, but different, which means that the Son is a distinct Being.

Homoousios

For Basil, homoousios meant that the Son’s substance is like the Father’s, implying distinct substances.  

Homoousios has two possible meanings. When two entities are said to be of the ‘same substance’ (homoousios), it can mean that they are a single substance or two distinct but identical substances. Show More

After Basil had moved away from the ‘similar substance’ formula of the Homoi-ousians, and had accepted the term homouousios, he continued to say that the Son’s substance is “like” the Father’s, implying two distinct substances:

Basil insists that “the Son, like the Father, is simple and uncompound” (Ayres, p. 204).

“He says that in his own view ‘like in respect of ousia’ (the slogan of the party of Basil of Ancyra) was an acceptable formula, provided that the word ‘unalterably’ was added to it, for then it would be equivalent to homoousios” (Hanson, p. 694) Show More

Basil said that homoousios corrects Sabellianism, for it keeps the Persons distinct. 

Basil wrote:

“This expression (homoousios) also corrects the fault of Sabellius for … (it keeps) … the Persons (prosopon) intact, for nothing is consubstantial with itself” (Hanson, pp. 694-5). (The Sabellians taught that the Father, Son, and Spirit are only one single Person.)

“Later, when he (Basil) had accepted homoousios as a proper term to apply to the Son, he still argued that it was preferable because it actually excluded identity of hypostases” (Hanson, p. 697).

Therefore, while Trinitarians understand homoousios as saying that the Father and Son are one substance, Basil explained it in a generic sense of two Beings (two distinct existences) with the same type of substance:

Adolf von Harnack “argued that Basil and all the Cappadocians interpreted homoousios only in a ‘generic’ sense … that unity of substance was turned into equality of substance” (Hanson, p. 696).

Basil remained a semi-homoiousian:

“Basil has moved away from but has not completely repudiated his origins” (Hanson, p. 694).

“Basil still seems to view the relationship between Father and Son in a fundamentally Homoiousian way” (Ayres, p. 190)

Hypostasis and Ousia

For Basil, the Persons are instances of divinity, just like people are instances of humanity. 

He regarded the Persons (hypostases) as particular concrete examples of a ‘generic’ Godhead (ousia), just like human beings are particular instances of a generic humanity. This is a clear indication that Basil thought of the Father and Son as distinct Beings:

Basil “discusses the idea that the distinction between the Godhead and the Persons is that between an abstract essence, such as humanity, and its concrete manifestations, such as man” (Hanson, p. 698). Show More

Therefore, Basil regarded human persons as appropriate examples of the divine Persons:

Basil assumed “that human persons are particularly appropriate examples” of “the nature of an individual divine person” (Ayres, pp. 207-8). 

“Basil discusses the individuation of Peter and Paul as analogous to the individuation of Father and Son” (Ayres, p. 207). 

Note that this also explains Basil’s understanding of the terms hypostasis and ousia.  Show More

Distinct Minds

Basil described the Father and Son as having distinct minds and wills, implying distinct Beings. 

“Basil … speaks of the Father choosing to work through the Son—not needing to. Similarly, the Son chooses to work through the Spirit, but does not need to” (Ayres, p. 208). 

“The Father, who creates by His sole will … the Son too wills” (Basil in De Spiritu Sancto). 

Basil said that the Son’s statements that he does the will of the Father “is not because He lacks deliberate purpose or power of initiation” but because “His own will is connected in indissoluble union with the Father.” Show More

Order among the Persons

Basil maintained a certain order among the Persons, implying the Persons are distinct Existences. 
“Father and Son are, indeed, the same in essence, but distinct at another level thus preserving a certain order among the persons” (Ayres, p. 195). 

For some unknown reason, he never described the Holy Spirit as homoousios with the Father and Son:

“Basil showed himself reluctant to apply homoousios to the Holy Spirit. … Homoousios was a word which applied particularly to the relation of the Son to the Father” (Hanson, p. 698). Show More

He also never described the Holy Spirit as God:

“While the Spirit is third in order and dignity, the Spirit is not third in an order of essences. Basil insists that the Spirit is to be accorded equal worship and honour with the Father and the Son, even if he is not willing to say directly that the Spirit is God in the same terms as Father and Son” (Ayres, p. 216). Show More

He referred to the Holy Spirit as third in rank:

“The Spirit is third in order and dignity” (Ayres, p. 216).

“The Spirit is third in order and even rank” (Hanson, p. 689). 

For Basil, the Father alone exists without cause. Since he teaches that Father and Son have the same substance, Basil was sensitive to the accusation that he could be accused of tritheism; three Ultimate Principles; three Beings who exist without cause and gave existence to all else:

“To speak of Father and Son as simply having the same ousia would be … to present him as logically another God” (Ayres, p. 190). 

To address this, Basil identified the Father alone as the ultimate Source:

“Let no one think that I am saying that there are “three ultimate principles … There is one ultimate principle of all existent things, creating through the Son and perfecting in the Spirit” (Hanson, p. 691). Show More

He maintained the priority of the Father:

“By the 370s Basil had evolved a formula stating that the activities of God all come from the Father, are worked in the Son, and are completed in the Spirit. In this formula Basil seems … to find a way to speak of the unity of divine action while still preserving the priority of the Father” (Ayres, p. 196).

Since Basil preserved a certain order among the Persons, refusing to say that the Spirit is homoousios and God, but describing the Spirit as third in order and dignity, and since he believed that the Father alone exists without cause, and maintained the priority of the Father, it is difficult to imagine that Basil believed that the Father, Son, and Spirit are a single existence.


Contemplation

Basil’s theology was not based on the Bible alone but on the Bible + ‘Contemplation’ (epinoia – ἐπίνοια). He explained epinoia as “concepts developed by the human mind” through “a process of reflection and abstraction.”

“For Basil, arguing that Father and Son are ‘unlike’ flies in the face of biblical material such as Col 1:15, Heb 1:3, and Phil 2:6.” As Basil read these texts, they “all … point to a community of essence between the generated and the one who has generated” (Ayres, p. 194). But how did Basil come to this conclusion? He answers:

“By ἐπίνοια [epinoia] we know that there is a unity of ousia between Father and Son” (Ayres, p. 194). 

Ayres explains epinoia as:

      • “Concepts developed by the human mind” (Ayres, p. 191-2),
      • “A process of reflection and abstraction” (Ayres, p. 192), and
      • “An intellectual contemplation of the reality of things” (Ayres, p. 193).

For Basil, we can only understand the Father, Son, and Spirit through “contemplation:”

Contemplation “throws away the letter and turns to the Lord” (Ayres, p. 219). 

“The contemplation of the Spirit necessary to understand the Spirit is itself at the core of Christian life” (Ayres, p. 219). 

That sort of contemplation is only available to “Christians who have attained ‘purity of heart’” (Ayres, p. 219). 

But Eunomius, Basil’s rival against whom he wrote three books, dismissed ἐπίνοια, as a way of gaining knowledge of God, as unreliable (Ayres, p. 191-2) and condemned it (Ayres, p. 193). He argued:

“If we know God only according to ἐπίνοια, then our knowledge is insignificant and our faith useless” (Ayres, p. 195).


Basil was a Philosopher.

It is traditional to accuse Arius of mixing the Bible with philosophy but the real culprits in this regard were the Cappadocians. Basil’s doctrine of God was based on pagan philosophy. Basil obtained the distinction between a common deity and the differentiation of Persons (as discussed above) not from the Bible but from pagan philosophy. The Cappadocians all relied on contemporary philosophy more than, for example, Athanasius and Hilary.

Influences

Ayres identifies “three basic influences on Basil’s account:”

“The first is Stoic terminologies about the relationship between general and individuated existence. … Stoics posited a universal … substrate (or ousia). … At the level of concrete existence individuals are also qualified by further qualities” (Ayres, p. 199-200). 

Secondly, “Neoplatonic-Aristotelian conceptions are used to interpret a basically Stoic scheme” (Ayres, p. 202). 

Thirdly, “we cannot, however, treat Basil’s distinction against a purely philosophical background. … It seems most likely that Basil’s evolution of the distinction occurred within a context where some such distinction was already clearly in the air” (Ayres, p. 202). 

The Cappadocians relied on philosophy:

Hanson concludes that “the Cappadocians all relied on the aid of contemporary philosophy more than … Athanasius and Hilary” (Hanson, p. 677). “A small work (by Basil) … at the end of Book V of Adversus Eunomium … is full of echoes of passages in Plotinus’ Enneads” (Hanson, p. 687)


Other Articles

The Arian Controversy, according to Wikipedia

This article is a criticism of the Wikipedia article on the ‘Arian Controversy,’ retrieved May 2025. It gives the Wikipedia article sentence by sentence and provides comments and quotes from the books on the subject that have been published over the past 50 years:

Hanson, R.P.C. – The Search for the Christian Doctrine of God – The Arian Controversy 318-381 (1987)

Williams, Rowan – Arius, Heresy & Tradition, (2002/1987)

Ayres, Lewis – Nicaea and its legacy, An Approach to Fourth-Century Trinitarian Theology (2004)

Anatolios, Khaled – Retrieving Nicaea (2011)

The green blocks quote verbatim from Wikipedia:

When did the Controversy begin?

Wikipedia: The Arian controversy was a series of Christian disputes about the nature of Christ that began with a dispute between Arius and Athanasius of Alexandria, two Christian theologians from Alexandria, Egypt.

I am sure Wikipedia means Alexander of Alexandria. See under “Beginning” of the article. The dispute between Arius and Alexander began in 318. Athanasius became involved only about two decades later:

“There was … no reason to regard Athanasius as a zealous supporter of the doctrine of Nicaea until at earliest his second exile (339-346)” (Hanson, p. 275).

More importantly, the Arian Controversy did not begin in the fourth century. The fourth-century controversy was a continuation of the controversy in the preceding centuries:

“We will find pre-existing deep theological tensions at the beginning of the fourth century. Controversy over Arius was the spark that ignited a fire waiting to happen, and the origins of the dispute do not lie simply in the beliefs of one thinker, but in existing tensions that formed his background” (Ayres, p. 20). 

“The views of Arius were such as in a peculiar manner to bring into unavoidable prominence a doctrinal crisis which had gradually been gathering … He was the spark that started the explosion, but in himself he was of no great significance” (Hanson, p. xvii-xviii).

“The conflict in the fourth century was one between two theological traditions, both of which were well established by the beginning of the century” (Lienhard).

The Core Issue

Wikipedia: The most important of these controversies concerned the relationship between the substance of God the Father and the substance of His Son

No. This was not the core issue. For example, the term homoousios (same substance) disappeared from the Controversy soon after Nicaea and only came back into the Controversy in the 350s:

“After Nicaea homoousios is not mentioned again in truly contemporary sources for two decades. … It was not seen as that useful or important” (Ayres, 96).

“What is conventionally regarded as the key-word in the Creed homoousion, falls completely out of the controversy very shortly after the Council of Nicaea and is not heard of for over twenty years” (Hanson).

“Homoousios was in fact a foreign body or stumbling block for all the people attending the council, without distinction, Arians and anti-Arians, and for this very reason it soon disappeared in the following debates” (P.F. Beatrice).

“Athanasius’ decision to make Nicaea and homoousios central to his theology has its origins in the shifting climate of the 350s” (Ayres, p. 144).

“He began to use it first in the De Deeretis … in 356 or 357” (Hanson, p. 438). (See here for more details.)

The core issue was something more fundamental, of which homoousios was only a symptom, namely, the question whether the Son is a distinct Person:

The ‘Arians’ said that he is a distinct Person (hypostasis).

The Nicenes believed He is part of the Father. Therefore, the Father and Son are a single Person (hypostasis), and the Son is homoousios with the Father, meaning that the Father and Son are a single substance:

“The way of using the word hypostasis characterized the two opposing parties for much of the fourth century; one preferred to speak of one hypostasis in God, the other of two (or three, if the Holy Spirit is considered). … These terms signal a profound difference in theology, one that touched not only the way God— Father, Son, and Holy Spirit—was understood, but also the way Christ’s person and saving work were described” (Lienhard).

“Behind the original controversy lie conflicting approaches to the Word’s generation’. To what extent can we think of it as the emergence of one distinct thing from another? How does one understand the distinction between God and Word, Father and Son: is this the distinction of two separate beings?” (Ayres, p. 3).

See here for a discussion.

The Father of Arianism

Wikipedia: The position advanced initially by Arius argued that the Son of God came after God the Father in both time and substance

By beginning the article by saying what Arius believed, Wikipedia implies that Arius was the founder of Arianism and a key driver in the Controversy. In reality, he was of no great significance:

“The people of his (Arius’) day, whether they agreed with him or not, did not regard him as a particularly significant writer. … Neither his supporters nor his opponents thought them (his writings) worth preserving. … He virtually disappears from the controversy at an early stage in its course” (Hanson, xvii).

“The views of Arius were such as … to bring into unavoidable prominence a doctrinal crisis which had gradually been gathering. … He was the spark that started the explosion. But in himself he was of no great significance” (Hanson, p. xvii).

“Arius’ own theology is of little importance in understanding the major debates of the rest of the century (after Nicaea)” (Ayres, 56-57).

“Arius’ own role in the ‘Arian controversies’ was comparatively small” (Lienhard, quoting Adolf Martin Ritter).

“It is virtually impossible to identify a school of thought dependent on Arius’ specific theology” (Ayres, 2).

Arius was not a leader. Ayres divides the participants in the Controversy into four groups. One group is the Eusebians (the followers of Eusebius), and Arius was one of them. In other words, Eusebius was the leader of what is traditionally known as ‘Arianism.’

“My second theological trajectory is the one in which we locate Arius himself. This loose alliance I will term ‘Eusebian’. When I use this term I mean to designate any who would have found common ground with either of Arius’ most prominent supporters, Eusebius of Nicomedia or Eusebius of Caesarea” (Ayres, p. 52).

“Arius too, far from being an original thinker, was simply one more adherent of the dyohypostatic (two hypostases) tradition” (Lienhard).

In fact, some of Arius’ views deviated from the mainstream ‘Arian’ view. For example, the ‘Arian’ Dedication Creed of 341 condemned some of his views:

It “deliberately excludes the kind of Arianism professed by Arius” (Hanson, p. 290).

It “does anathematize doctrines associated … with Arius” (Ayres, p. 120).

For example, the Creed anathematizes all who say: “that either time or occasion or age exists or did exist before the Son was begotten” (Hanson, p. 286).

Time before the Son

Wikipedia: The position advanced initially by Arius argued that the Son of God came after God the Father in both time and substance

It is not correct to say that Arius believed that the Son of God came after God the Father in time. Arius always said that the Son existed before time and the creation even existed. Therefore, he said ‘There was when the Son was not,’ without mentioning the word “time.” In his view, from the perspective of the Creation, the Son has always existed:

“Although we cannot describe the Son’s birth in temporal categories, we should not say that the Son is coeternal” (Ayres, pp. 54-55, describing Arius’ view).

Arius wrote that the Son “exists … before times and before ages” (Hanson, p. 6), and was “begotten timelessly by the Father … before aeons … begotten timelessly before everything” (Hanson, p. 8). (An aeon is “an indefinite and very long period of time.”)

I am not sure what it could mean to say that Arius said that the Son of God came after God the Father in substance. Arius believed that the Father’s substance is different from the Father’s.

The Nicenes and Trinitarians

Wikipedia: This conflicted with the Trinitarian faction initially advanced by Athanasius which argued that the Christ was coeternal and consubstantial with God the Father

Firstly, this seems to imply that Athanasius developed a new theology. He did not. He followed Alexander.

“Alexander’s theology found its most famous advocate in his successor Athanasius” (Ayres, p. 45).

Secondly, there was no “Trinitarian faction” at the time. The Nicenes were not Trinitarians. In Trinitarian theology, the Father, Son, and Spirit are a single Being existing as three hypostases (Persons). In contrast, in Arius’ time, the Nicenes believed that the Father, Son, and Spirit are a single hypostasis (Person).

“Athanasius’ most basic language and analogies for describing the relationship between Father and Son primarily present the two as intrinsic aspects of one reality or person” (Ayres, p. 46).

“He [Athanasius] had attended the Council of Serdica among the Western bishops in 343, and a formal letter of that Council had emphatically opted for the belief in one, and only one, hypostasis as orthodoxy. Athanasius certainly accepted this doctrine at least up to 359, even though he tried later to suppress this fact” (Hanson, p. 444).

“During this same period [the 350s] the miahypostatic [one hypostasis] tradition is represented most fully by Athanasius” (Lienhard).

“The fragments of Eustathius that survive present a doctrine that is close to Marcellus, and to Alexander and Athanasius. Eustathius insists there is only one hypostasis“ (Ayres, p. 69).

Constantine’s Motive

Wikipedia: Emperor Constantine, through the Council of Nicaea in 325, attempted to unite Christianity and establish a single, imperially approved version of the faith

Yes, that is what Constantine attempted to do, but his interest was not the ‘truth.’ Before the Council, he wrote a letter and described the matter as trivial.

“In 324 the Emperor Constantine … (who) assumed control of the whole empire, took an interest in the dispute. Constantine wrote to Alexander and Arius telling them to stop quarrelling about what seemed to him to be such a small matter. Soon, however, Constantine began to see their dispute as more serious” (Ayres, pp. 17-18).

His motive was to unite the church because a division in the Church could also cause his empire to divide.

“Since Constantine desired that the church should contribute to the social and moral strength of the empire, religious dissension was a menace to the public welfare, and if necessary, secular authority might be exercised for its suppression” (Boyd) [W.K. Boyd, The Ecclesiastical Edicts of the Theodosian Code (1905)].

“Constantine’s attitude reflects deeply embedded Roman attitudes about the social function of religion” (Ayres, p. 88).

Council of Nicaea

Wikipedia: Emperor Constantine, through the Council of Nicaea in 325, attempted to unite Christianity and establish a single, imperially approved version of the faith

A second observation from this sentence is that Nicaea 325 was Constantine’s meeting. It was not a church council. It was a meeting of the Roman government to which bishops were invited.

“The history of the period shows time and time again that local councils could be overawed or manipulated by the Emperor or his agents. The general council was the very invention and creation of the Emperor. General councils, or councils aspiring to be general, were the children of imperial policy and the Emperor was expected to dominate and control them” (Hanson, p. 855).

Cause of the divisions

Wikipedia: Ironically, his efforts were the cause of the deep divisions created by the disputes after Nicaea

The Nicene Council did not cause the Controversy. The same divisions that existed before Nicaea continued after Nicaea. As stated above, these deep divisions carried over from the third century. 

Schism

Wikipedia: there was no formal schism … 

This implies that the Church was a single organization under a single leader. In reality, during the first three centuries, Christianity was a persecuted minority. There was no single organization that could be divided.

In the fourth century, the emperors acted as the head of the Church. The Emperor was the ultimate judge in doctrinal disputes.

“If we ask the question, what was considered to constitute the ultimate authority in doctrine during the period reviewed in these pages, there can be only one answer. The will of the Emperor was the final authority” (Hanson, p. 849).

Therefore, when the Empire became divided between different emperors, the Church also became divided. For example:

In the 340s, the Empire was divided between Eastern and Western emperors. Therefore, the Church also became divided.

In the 350s, the Empire was once again under a single emperor, who forced the Church to unite.

For much of the 360s-370s, the Empire was again divided East and West, allowing the Western and Eastern Churches to drift apart as well.

Furthermore, there seems to be an unjustified emphasis on the Christianity of the Roman Empire. Some of the other European nations also converted to Christianity. The Germanic tribes, chiefly the Goths and the Vandals, had been converted to Christianity through the Arian missionary Ulfilas and had their own church structures.

Duration

Wikipedia: These disagreements divided the Church into various factions for over 55 years, from the time before the First Council of Nicaea in 325 until after the First Council of Constantinople in 381

However:

As stated above, the Controversy did not begin in the fourth century but continued the third-century Controversy, as reflected, for example, in the dispute between the bishops of Rome and Alexandria in the middle of the third century.

Furthermore, the Controversy did not end in 381. In 381, the Roman Empire made Nicene theology the only legal religion of the Roman nation, but the other European nations remained ‘Arian.’ In the fifth century, the Western Empire fragmented into several kingdoms, and they were all Arians.

“Similarly, older narratives in which a clear end is identified fly in the face of evidence that controversy continued into the fifth century” (Ayres, p. 267).

Therefore, it would be more accurate to say that the Controversy divided the Church for centuries.

Edict of Thessalonica

Wikipedia: Inside the Roman Empire, the Trinitarian faction ultimately gained the upper hand through the Edict of Thessalonica, issued on 27 February AD 380, which made Nicene Christology the state religion of the Roman Empire, and through strict enforcement of that edict.  

This is essentially correct. The victory of the Nicene faction did not come at the so-called Second Ecumenical Council of 381, but through a Roman Law published in the preceding year. Theodosius outlawed all non-Nicenes factions, confiscated their churches, and prohibited them from meeting for worship or from living in the cities: 

“On January 10 (381), Theodosius issued an edict … No church was to be occupied for worship by any heretics, no heretics were to gather together for worship within the walls of any town” (Hanson, p. 805). 

“Immediately after the council ended, at the very end of July 381, Theodosius issued an Edict confirming its conclusions. This Edict is known as Episeopis tradi. The first words are:

‘We now order that all churches are to be handed over to the bishops who profess Father, Son and Holy Spirit of a single majesty, of the same glory, of one splendour, who establish no difference by sacrilegious separation, but the order of the Trinity by recognizing the Persons and uniting the Godhead’” (Hanson, pp. 820-1).

Unitarinism

Wikipedia: However, outside the Roman Empire, Arianism and other forms of Unitarianism continued to be preached for some time (without the blessing of the Empire), but it was eventually killed off

Depending on the definitions, Arianism was not Unitarianism. The Arians believed in the existence of three divine Beings.

Arius

“We have to resist the anachronistic characterization of him (Arius) as an antitrinitarian theologian.” “He writes simply, ‘So there are three hypostaseis,’” meaning “the set of beings that form the object (or objects) of Christian confession. … the three hypostaseis seemingly form a certain unity” (Anatolios, p. 47-48).

Arians

The Dedication Creed, a statement of the Eastern (Arian) Church, says: “They are three in hypostasis but one in agreement” (Hanson, p. 286).

The Eusebians (Arians) confessed “three in hypostasis but one in agreement” (Ayres, p. 118).

The Nicenes were the ‘Unitarians’ because they believed that the Father, Son, and Spirit are a single Person. 

Athanasius

“Athanasius’ gut reaction is that there can be only one eternal reality and source, and that proposing more than one hypostasis would imply a dualism” (Ayres, p. 48).

The “clear inference from his (Athanasius’) usage” is that “there is only one hypostasis in God” (Ayres, p. 48).

“Just what the Council intended this expression [homoousios] to mean is set forth by St. Athanasius as follows … That the Son is not only like to the Father, but inseparable from the substance of the Father, that he and the Father are one and the same” (Philip Schaff).

Western Manifesto at Serdica

“We have received and have been taught this … tradition: that there is one hypostasis, which the heretics (also) call ousia, of the Father and of the Son and of the Holy Spirit” (Hanson, p. 301, quoting the Western (Nicene) Manifesto at the Council of Serdica). (See here for details.)

Therefore, scholars now conclude that Athanasius’ theology is unitarian. The same applies to the theology of the Sabellians, which is similar to Athanasius’ theology:

Athanasius

“Studer’s account [1998] here follows the increasingly prominent scholarly position that Athanasius’ theology offers a strongly unitarian Trinitarian theology whose account of personal differentiation is underdeveloped” (Ayres, p. 238).

Sabellians

Ayres refers to “supporters of Nicaea whose theology had strongly unitarian tendencies. Chief among these was Marcellus of Ancyra” (Ayres, p. 431).

Athanasius was similar to Sabellians.

“Although Athanasius’ theology was by no means identical with Marcellus’, the overlaps were significant enough for them to be at one on some of the vital issues—especially their common insistence that the Son was intrinsic to the Father’s external existence” (Ayres, p. 106).

“The fragments of Eustathius that survive present a doctrine that is close to Marcellus, and to Alexander and Athanasius. Eustathius insists there is only one hypostasis“ (Ayres, p. 69).

Modern Trinity Doctrine

The modern Roman Catholic Church and the Eastern Orthodox Church, as well as all Protestant denominations, have generally followed the Trinitarian formulation, though each has its own specific theology on the matter

This seems correct. However, modern Trinitarianism deviates from Nicene theology:

“Modern Trinitarianism … has barely engaged with it (pro-Nicene theology) at all” (Ayres, p. 7).

“Even modern theologies wishing to uphold a Nicene faith have frequently failed to sustain the theological practices that shaped and made possible that faith” (Ayres, p. 6).

Conclusion

So far, this article has discussed only the introduction in Wikipedia’s article, but has discovered the following errors:

According to Wikipedia: In Reality:
The Controversy began in the fourth century. The Controversy continued the controversy of the previous century.
The core issue is reflected by the term homoousios. The core issue was whether the Son is a distinct Person. The Nicenes used the term homoousios to say that the Father and Son are a single substance.
Arius was the founder of Arianism and a key driver in the Controversy. He was of no great significance. Eusebius was the leader of the so-called Arians.
Arius argued that the Son of God came after God the Father in time. Arius claimed that the Son was begotten before time existed.
The Nicene Council caused divisions. The same divisions that existed before Nicaea continued after Nicaea.
There was no formal schism. There was no single organization that could be divided.
These disagreements ended at the First Council of Constantinople in 381 When the Romans in 381 made Nicene theology their sole legal religion, the other nations remained ‘Arian.’
The Nicenes were Trinitarians, believing in three Persons in God. The Nicenes believed that the Father and Son are a single Person. They were Unitarians.
The Arians were Unitarians. The Arians believed in a trinity of three divine Beings. 
Modern Trinitarianism follows Nicene theology. Modern Trinitarianism fails to sustain Nicene theology.

The reason for all these errors is that Wikipedia follows the traditional account of the Arian Controversy, as was explained by scholars until the end of the 19th century. During the 20th century, research has shown that the traditional account is the account of the winner and a complete travesty. Therefore, compared to the books published during the past 50 years, the Wikipedia article distorts the history of the Controversy.

“The four decades since 1960 have produced much revisionary scholarship on the Trinitarian and Christological disputes of the fourth century” (Ayres, p. 2).

“A vast amount of scholarship over the past thirty years has offered revisionist accounts of themes and figures from the fourth century” (Ayres, p. 2, writing in 2004).

The “conventional account of the Controversy, which stems originally from the version given of it by the victorious party, is now recognised by a large number of scholars to bea complete travesty” (Hanson).

The traditional account stems from Athanasius’ polemical strategy:

“Athanasius’ engagement with Marcellus in Rome seems to have encouraged Athanasius towards the development of” “an increasingly sophisticated account of his enemies;” “the full flowering of a polemical strategy that was to shape accounts of the fourth century for over 1,500 years;” “a masterpiece of the rhetorical art” (Ayres, p. 106-7).

Since anybody can edit Wikipedia’s article, and since the majority of the Church accepts the traditional account of the Arian Controversy because it supports the traditional Trinity doctrine, I cannot see that Wikipedia’s article will soon be revised to reflect the true history. I tried, but I have been banned from Wikipedia.