Why was Theodosius successful in ending the Arian Controversy?

In the conventional account of the Arian controversy, the council of Constantinople in the year 381 made an end of that controversy. In reality, the controversy was brought to an end by Emperor Theodosius in the year 380 through the Edict of Thessalonica, in which he outlawed all non-Trinitarian forms of Christianity.

The emperor’s edict was more clearly Trinitarian than the Constantinople Creed of 381. While the Creed identifies the “one God” as the Father, the emperor’s creed identified “the one deity” as the Trinity:

Let us believe in the one deity of the Father, the Son and the Holy Spirit, in equal majesty and in a holy Trinity

Of those who oppose his edict, it said:

They will suffer … the punishment of our authority which … we shall decide to inflict.

On 26 November 380, two days after he had arrived in Constantinople for the first time, Theodosius expelled the Homoian bishop, Demophilus of Constantinople, and appointed Gregory of Nazianzus, one of the Cappadocian Fathers … patriarch of Constantinople. (Theodosius I – Wikipedia – copied 25 Nov 2021)

“In January of the following year (381), another edict forbade the heretics [non-Trinitarians] to settle in the cities” (Boyd, William Kenneth (1905)) 1The Ecclesiastical Edicts of the Theodosian Code. Columbia University Press. p45-46

Therefore, when Theodosius in May 381 summoned a council of bishops at Constantinople, all other views were already outlawed and only people who accepted the Nicene Creed were admitted into this ‘ecumenical’ council:

“Thirty-six Pneumatomachians arrived but were denied admission to the council when they refused to accept the Nicene creed.” (First Council of Constantinople – Wikipedia Retrieved 25 Nov 2021)

Gregory of Nazianzus—the leader of the Nicene party in the city—presided over part of the Council and vehemently opposed any compromise with the Homoiousians (those who believed that the Son’s substance is “similar” to the Father’s). 2Lewis Ayres – Nicaea and its legacy – Oxford University Press

(The homoi-ousians were the ‘Arians’ who were the closest to the Homo-ousians (the supporters of the Nicene Creed). Therefore, since Gregory of Nazianzus vehemently opposed any compromise with the Homoiousians, he also opposed compromise with any of the other views.)

“Several Emperors had attempted to bring an end to the Arian controversy. Constantine, Constans, Constantius … All had failed because … they in fact were not supported by a consensus in the Church at large. Theodosius succeeded because … (he was) backed by a consensus in the Church.” (Hanson Lecture)

The emperors whom Hanson mentions all opposed the homoousian view, exiled homoousian bishops, and appointed bishops that supported their points of view. One must remember that the church became part of the governance structure of the Roman Empire. Boyd wrote:

“The political and social power acquired by bishops … made their election in the days of the later Roman Empire … a matter of public importance. … Consequently, the election of patriarchs was often the occasion of an ecclesiastical synod and the emperors, through their relation to the synods, which they often convened and attended, might exercise a direct influence on elections. Constantine wrote to the council and people of Antioch not to choose Eusebius of Caesarea as bishop of that city. Constantius convened “an assembly of bishops of Arian sentiment” and deposed Paul of Constantinople” (Boyd) 3The Ecclesiastical Edicts of the Theodosian Code page 64

I am not sure that Hanson is right about this “consensus.” If there was consensus, why did he have to exile the homoian bishop of the capital of the empire (Constantinople)? (See Theodosius I – Wikipedia – copied 25 Nov 2021) Furthermore:

Williams & Friell wrote that, by 379, when Theodosius I succeeded Valens, Arianism was widespread in the eastern half of the Empire, while the west had remained steadfastly Nicene. (Williams, Stephen; Friell, Gerard (1994). Theodosius: The Empire at Bay. B.T. Batsford Ltd. ISBN 0-300-06173-0, pp. 46–53)

Church historian Sozomen wrote: Theodosius made known by law his intention of leading all his subjects to the reception of that faith which was professed by Damasus, bishop of ROME, and by Peter, bishop of ALEXANDRIA. (Sozomen’s Church History VII.4)

On the other hand, Hanson stated that in the year 375 there was an incident where the Pope of Rome and the archbishop of Alexandria opposed Basil of Caesarea, the champion of Nicene orthodoxy in the East. (See, Lecture)

So, my question is one for the church historians: Did a consensus exist as Hanson suggested, or was Theodosius successful because he used the might of the sword more effectively than his predecessors? I regard this as an extremely important question because it will determine whether the acceptance of the Trinity doctrine by the church was the decision of:

    • A Roman Emperor, supported by a faction in the church, or by
    • A majority of church officials.


  • 1
    The Ecclesiastical Edicts of the Theodosian Code. Columbia University Press. p45-46
  • 2
    Lewis Ayres – Nicaea and its legacy – Oxford University Press
  • 3
    The Ecclesiastical Edicts of the Theodosian Code page 64

Did Arius corrupt theology with pagan philosophy?


Over the centuries, Arius was always accused of mixing philosophy with theology. This article shows that that is not true. There are two ways in which Greek philosophy could have influenced the debate in the fourth century:


In Greek philosophy, the Logos was the Intermediary between God and creation. The Christian theologians of the second and third centuries (the Apologists) identified the Son of God as that Greek Logos. Consequently, Logos-theology was orthodoxy when the Arian Controversy began. It was accepted by most delegates to Nicaea. Therefore, Arius did not bring Logos-theology into the church. In fact, Arius was not comfortable with Logos-theology.

Classical Theism

Classical Theism includes principles such as that God is immaterial, unable to change or do evil, exists outside time, and incapable of suffering or feeling pain. These principles from Greek philosophy were accepted by Christian theologians in the centuries before Arius and all theologians of the fourth century accepted these principles. Theologians, generally accept these principles even to this day.

Arius was not a philosopher.

Our authors conclude:

Arius. “is not a philosopher, and it would be a mistake to accuse him of distorting theology to serve the ends of philosophical tidiness. On the contrary: the strictly philosophical issues are of small concern to Arius.” (RW, 230)

The Cappadocians were philosophers.

However, while Arius was traditionally accused of using philosophy, according to R.P.C. Hanson, it was the Cappadocian fathers who, in the years 360-380, developed the Trinity Doctrine (pro-Nicene theology) as a way to explain “how the Nicene creed should be understood” (LA, 6), who were deeply influenced by philosophy. “The Cappadocians … were all in a sense Christian Platonists.” (RH, 863) 


Arius is accused of philosophy.

Scholars have often accused Arius of combining Christian theology with philosophy. For example:

Up to the 1830s, “it had been customary to associate the Arian system primarily with Neoplatonism” (RW, 3).

Gwatkin (1900) described Arianism as the result of “irreverent philosophical speculation” and “almost as much a philosophy as a religion.” (RW, 9)

“Harnack’s … sees Aristotelian Rationalism as the background of Arius’ system.” (RW, 6)

Even modern writers sometimes say, for example: “The heretics typically took pre-existing Christian or Jewish tradition (and) combined it with certain philosophical rhetoric.” (Wedgeworth)

The purpose of this article is to determine whether Arius and/or his opponents were primarily philosophers.

Authors quoted

This article series is largely based on three books:

RH = Bishop RPC Hanson
The Search for the Christian Doctrine of God –

The Arian Controversy 318-381, 1987

RW = Archbishop Rowan Williams
Arius: Heresy and Tradition, 2002/1987

LA = Lewis Ayres
Nicaea and its legacy, 2004
Ayres is a Professor of Catholic and Historical Theology

These are world-class scholars and Trinitarians who have made in-depth studies of the Arian Controversy of the fourth century and are regarded as specialists in this field.

Forms of Philosophy in Theology

There are two forms of philosophy that could have influenced theology, namely:

      • The general principles of Classical Theism and
      • The more specific application of such principles in the traditional Christian Logos-theology.


The Logos of Greek Philosophy

In Greek philosophy, the Logos was the Intermediary between God and creation.

In Greek philosophy:

The Supreme Being is immutable, abstract, and immaterial.

For that reason, He is unable to communicate directly with our world of change, decay, transitoriness, and matter.

Therefore, He brought forth the divine Logos or nous as His agent for creating the world and for revealing Himself in the world. (Hanson)

The Logos of the Apologists

The Apologists identified the Son as that Greek Logos.

These concepts from Greek philosophy were generally accepted in the intellectual world of the Roman Empire. The Christian Apologists (the pre-Nicene fathers), therefore, found it effective to identify the Biblical Son of God with the divine Logos of Greek philosophy; both before and after He ‘became a man’. (Hanson) For example:

“Ever since the work of Justin Martyr, Christian theologians had tended to use the identification of the pre-existent Son with some similar concept in contemporary Middle Platonism as a convenient philosophical device” (RH, 22-23).

The Apologists’ Logos-theology, therefore, was strongly based on Greek philosophy.

Logos-theology was orthodoxy.

Logos-theology was orthodoxy when the Arian Controversy began.

Logos-theology was the standard explanation of the Son when the Arian Controversy began. Both Arius and his opponents inherited and accepted Logos-theology. For example:

“Our mistake is to try to interpret him (Arius) in terms of a theology with which he was not at home, the Logos-theology he shares with his opponents.” (RW, 12)

Most delegates to Nicaea accepted Logos-theology. The West was poorly represented at Nicaea (Erickson) and “the great majority of the Eastern clergy (at Nicaea) … were simply concerned with maintaining the traditional Logos-theology.”1Frend, W.H.C.: The Rise of Christianity

Hanson uses the term “Logos-doctrine” for “the theological structure provided by the Apologists” and confirms that it was “the basic picture of God with which the great majority of those who were first involved in the Arian Controversy were familiar and which they accepted.” (Hanson’s article)

Arius did not bring Logos-theology into the church.

While writers have often accused Arius of attempting to bring pagan philosophy into the church, the above shows that pagan philosophy, in the form of Logos-theology, had entered the church during the centuries before Arius. It was something that both Arius and his enemies inherited and accepted. Arius did not attempt to bring it into the church.

Arius was not comfortable with Logos-theology.

On the contrary, as Williams stated, Arius was not “at home” with Logos-theology (RW, 12-13). It was not part of his language.

Classical Theism

What is Classical Theism?

“‘Classical theism’ is the name given to the model of God we find in Platonic, neo-Platonic, and Aristotelian philosophy.” (Springer) In this model, God is, amongst others:

      • “Unqualifiedly perfect,”
      • Immutable, meaning unable to change or do evil,
      • Impassible, meaning incapable of suffering or feeling pain,
      • An “absolute unity,” meaning that He does not consist of parts,
      • Fully self-sufficient, including that He exists without cause,
      • “Atemporal,” meaning that He exists outside time and is not subject to time,
      • Immaterial, meaning that He is free from all limitations of space and matter.

The pre-Nicene fathers accepted Classical Theism.

Arius inherited these concepts from the church fathers. For example:

“The Christian theologians of the second and third centuries” used “this particular type of Platonism … for explaining the relation of the Father to the Son.” (RH, 85-86)

Arius received “this type of Platonism … through Clement and Origen.” (RH, 87) (Clement and Origen are famous Alexandrians from the third century.)

Arius’ opponents accepted Classical Theism.

Arius did use such principles from Classical Theism in his arguments but if we judge Arius to be a philosopher for that reason, then all theologians in the fourth century were philosophers for they all accepted these principles. For example:

“For all the writers of the early Church, that freedom from time, matter, fate and chance expressed in the classical philosophical attribution of negative predicates to God (immateriality, immutability, and so on) was self-evidently the only way to make sense of scriptural data … Athanasius is at one with Arius here.” (RW, 111)

“All Greek-speaking writers in the fourth century were to a greater or lesser degree indebted to Greek philosophy.” (RH, 858-9)

All fourth-century theologians accepted Classical Theism.

“It would … be absurd to deny that discussion and dispute between 318 and 381 were conducted largely in terms of Greek philosophy.

The reason for this was … a realization that the deepest questions which face Christianity cannot be answered in purely biblical language, because the questions are about the meaning of biblical language itself.” (RH, xxi)

“The fourth-century Fathers thought almost wholly in the vocabulary and thought-forms of Greek philosophy.” (Hanson’s Article)

Hanson wrote:

“One can draw up a rough list of the general presuppositions derived from contemporary philosophy which were likely to occupy the mind of any Christian theologian in the fourth century:

        • reality meant ontological permanence so that God, the highest form of reality, is most immutable of all;
        • and he cannot in any way involve himself with pathos (process, change or flux or human experience)” (RH, 859)

He says:

“These did not necessarily cancel nor obscure Biblical ideas and assumptions in the minds of those who held them, but they certainly coloured and shaped their general outlook.” (RH, 859)

“Christians were capable of using Platonist terms without necessarily being Platonists.” (RH, 861-2)

Arius was not a philosopher.

For these reasons, in contrast to the accusations listed above, our authors conclude that Arius was not a philosopher:

“We misunderstand him completely … if we see him as primarily a self-conscious philosophical speculator. … Arius was by profession an interpreter of the Scriptures.” (RW, 107-108)

“He is not a philosopher, and it would be a mistake to accuse him of distorting theology to serve the ends of philosophical tidiness. On the contrary: the strictly philosophical issues are of small concern to Arius.” (RW, 230)

“It is not just to dismiss him as one wholly preoccupied with philosophy. … His chief source was necessarily not the ideas of Plato or Aristotle or Zeno, but the Bible.” (RH, 98)

The Cappadocians were philosophers.

While Arianism is often accused of corrupting theology with philosophy, the shoe is on the other foot. Pro-Nicene theology was developed in the period 360-380 by essentially the three Cappadocian fathers, and they were, according to R.P.C. Hanson, deeply influenced by philosophy:

No philosophers before the Cappadocians

“Before the advent of the Cappadocian theologians there are two clear examples only of Christian theologians being deeply influenced by Greek philosophy.” (RH, 862) However, they did not have much influence:

“One is … Marius Victorinus … [who] had no influence that can be ascertained on his contemporaries.” (RH, 862)

“The other … is the Neo-Arian theologians Aetius and Eunomius … [who were] repudiated by almost all other Christian parties, pro-Nicene or anti-Nicene.” (RH, 862-3)

The Cappadocians were Christian Platonists.

“The Cappadocians, however, present us with a rather different picture. … They were all in a sense Christian Platonists.” (RH, 863)

Basil of Caesarea

“The debt of Basil of Caesarea to philosophy is undeniable” (RH, 863). “He … uses arguments drawn from several different philosophical traditions … along with arguments drawn from Scripture and tradition” (RH, 864). “Basil knew something of the work of Plotinus and consciously employed both his ideas and his vocabulary when he thought them applicable.” (RH, 866)

Gregory of Nazianzus

“Gregory of Nazianzus … certainly was deeply influenced by Platonism” (RH, 867). “In Trinitarian contexts, Gregory parallels Plotinus’ nous (mind) to the Father, and the Logos to the Son, and his thought of God as simple as ‘first ousia’, ‘first nature’ (Physis), the ‘first cause’ … all resemble doctrines of Plotinus.” (RH, 867)

Gregory of Nyssa

“Gregory of Nyssa … was more concerned than they (the other two Cappadocians) to build a consistent philosophical account of Christianity. He had therefore much more need of philosophy than they. … It is impossible to deny that he was influenced by the work of Plotinus.” (RH, 868)

What type of philosophy did Arius prefer?

Both RPC Hanson and Rowan Williams discuss the type of philosophy which Arius preferred, but they come to different conclusions:

Hanson proposes that “Middle Platonist philosophy” was a strong “candidate for the philosophical source of Arius’ thought.” (RH, 85-86)

But Williams thinks that “Arius’ metaphysics and cosmology … is of a markedly different kind from … ‘Middle Platonism'” (RW, 230) and that Arius “stands close to Plotinus and his successors.” (RW, 230)

Parallels to Middle Platonism

The following are some of the parallels which Hanson sees:

In both Arius and Middle Platonism, God and things exist ‘beyond’ time. “Arius … held that the Son was produced before all ages but yet there was a time when he did not exist.” (RH, 86)

Both Arius and Middle Platonism have a “drastic subordination of the Son to the Father.” (RH, 87)

In philosophy, Arius is ahead of his time.

Williams, therefore, concludes as follows:

“In philosophy, he is ahead of his time; he … presses the logic of God’s transcendence and ineffability to a consistent conclusion.” (RW, 233)

“And here is a still stranger paradox – his apophaticism (knowledge of God) foreshadows the concerns of Nicene theology later in the fourth century, the insights of the Cappadocians, or even Augustine.” (RW, 233)

Other Articles


  • 1
    Frend, W.H.C.: The Rise of Christianity