# "381: how the church as we know it was made"

The church which defines our world now is in a significant way the one which emerged out of sixty years of controversy from the Council of Constantinople in 381. I've been charting what happened, why, and the ongoing legacy.

Published on: 5 Oct 2025 

Athanasius defined the fourth century. Not that he was a god, or even a king, or that he always got his way. But he wrote the history books. His tale of an epic battle fought tooth-and-nail between Arian heretics and him and his loyal allies has come to be the standard account of how, over the course of the fourth century, the Church redefined what orthodoxy means and how it is declared and identified.

The result was the Nicene Creed. It had been first written for a very particular polemical purpose in 325, but later found itself the centre of a strange theological revival, and was finally revised in a council at Constantinople in 381. In so doing, the bishops assembled a recognisable 'Nicene' tradition which is still one of the defining features of planet Earth.

For better and for worse, the church as we know it has a capacity both for great humility, faith and submission to the mystery of God, but it also has a capacity for great intolerance. This is the church created in 381.

To understand the church as we know it today, then, we need to understand the complex, confusing journey from 325 to 381.

Athanasius' chronicle of that journey is temptingly simple. The only problem with it is that it isn't true. Indeed, his 'history' was never meant to function as an all-encompassing narrative of Church history, to be read for centuries ever after. His accounts function as polemics, meant to cajole, condemn and persuade his readers in his own time of his vision for their future.

Nevertheless, whatever Athanasius' real significance in how his times unfolded, his witness is important. He fully inhabited his times, often in the middle of the fray. Whether or not we buy Athanasius' portrayal of himself as fighting the good fight, he was certainly a fighter. By looking through his eyes, then, we can get a perspective on how the Church as we know it came to be.

So it makes sense to start with him. As a young priest in his native Alexandria, he became tangled up in a controversy which would come to define his career. A strong-minded and fearless young priest had begun to preach. His name was Arius.

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According to the Egyptian tradition, Alexander, the bishop of Alexandria, was the nineteenth in a direct line of succession from Mark the Evangelist himself. With a great deal of justice, he would have regarded himself as one of the most important Christian leaders in the world, and at least the equal of the bishop of Rome.

Small wonder, then, that the insubordination that plagued his diocese bothered him. First Erescentius had started a schism, disputing the rule he used for calculating the date of Easter.

Then there was Meletius. During the persecution under the Roman emperor Diocletian, Meletius had already rubbed a few people the wrong way: while other bishops were in hiding or in prison, he took the initiative to resolve problems and ordain priests without properly consulting the absent bishops' representatives. Perhaps it was intended kindly: it was seen as meddling. Now Meletius accused Alexander of being too soft on Christians who had caved into the threat of torture and made sacrifices to the pagan cults. When he decided Alexander was never going to match his high rigorist standards, he broke away, too.

Alexander must have longed for the relatively good order of the Greek and Roman churches, where bickering subordinates were generally willing to let their bishop have the last say. The throne of St Mark was in trouble. If Christ's body wasn't to get chopped up any more than it already was, he needed to establish his personal authority.

This was the context in which Arius, a young firebrand priest, steps onto stage right. He surely knew his own bishop's teaching: God is one substance and one essence, unchangeable, indivisible. Christ his Son is in every way God: God from God, light from light, true God from true God, eternally begotten of the Father before all ages. How else could Christ, by adopting human flesh, mediate the transcendent God to fallen humanity?

But Arius didn't like this one bit. If God is unchangeable, how could he adopt flesh? That suggests he was not flesh, and then became flesh. And in any case, if the martyrs were right to give up their lives to know God, he must have the perfect, uncompromising transcendence which the martyrs so admired. But how can God adopt flesh, never mind suffer and die on a cross, without compromising that transcendence? Something had to give. For Arius, the solution was to modify the relationship between the Father and the Son.

Arius accepted that Christ had to be in some sense divine, in order to mediate God to humanity. But he denied that he was quite as much God as God is. He has something like his Father's essence, not in a co-equal way, but rather in a derivative way. This makes sense of Father-Son language, which suggests the Father came first, and the Son came next, a derivative of the Father. So the Son is God from God, but not true God from true God. The Son was begotten in time, and is not eternal: only God the Father himself is eternal.

At another time in another place, Arius might have passed for a creative, independent thinker without much notice. But Arius was directly contradicting Alexander just as the latter was desperate to assert his authority. It got ugly.

Alexander called a council of local bishops in about 320. The council condemned Arius and removed him from his post as priest. In response, Arius went on the campaign trail, visiting bishops in Palestine and Asia Minor who he thought would be sympathetic to his theology. Shortly afterwards, he returned to Alexandria, triumphantly brandishing vindications from two councils, one in Jerusalem and one in Bithynia. He wasn't going to make it easy for Alexander.

Luckily for Alexander, the Emperor Constantine had just united the eastern and western halves of the Empire. He had famously converted to Christianity after seeing the sign of the cross at the Battle of Milvian Bridge in 312, and saw the bishops as means towards his mission of uniting the Empire under one government and one God. Constantine had been made aware of the dispute between Arius and Alexander, and he didn't want schisms in the church any more than Alexander did.

He called a council in his own palace in Nicaea, paying the travel expenses and hotel bills of all the bishops in attendance. For those bishops, many carrying the scars of torture they had endured under Diocletian, it must have been a bewildering experience. Alexander was in attendance. His secretary was Athanasius.

In 325, the council condemned Arius. To avoid anyone else following in his path, they produced a statement of faith, designed to exclude Arius' teaching, no matter who taught it. This statement of faith is now known as the Nicene Creed.

The council also fixed the date of Easter to boot. Alexander must have been relieved.

You might have thought that would have been the end for Arius. In fact, Constantine engineered his re-admittance into the church as soon as 328. Arius died in peace in 336. Constantine's mission wasn't to purge the church, but to unite the church. As long as all sides worshipped God and could live in peace, he wanted as many people as possible included. His mission was unity, not uniformity.

Bishops like Eusebius of Caesarea in Syria got this. He had been provisionally excommunicated on suspicion of Arianism in 325, but was reconciled at Nicaea given the chance to explain himself and sign up to the Nicene Creed. No sooner had he done this, however, than he had started explaining to the faithful back home how they could carry on believing that the Son was not really eternal, even as the Creed was designed to exclude exactly such a claim. While Eusebius might seem duplicitous, at the time, this was exactly the kind of tolerant pragmatism that Constantine asked of the bishops: as long as they didn't cause more out-and-out conflict.

Alexander didn't have long to enjoy the peace of Nicaea. He died just a few years afterward in 328. The throne of St Mark passed to Athanasius.

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The peace didn't last long. Just as Athanasius was donning his mitre, Eusebius was plotting against Eustathius the bishop of Antioch, and engineered his deposition. In his defence, Eusebius accused Eustathius of the long-condemned heresy, Sabellianism. Then in 335, he followed up by deposing Marcellus, the bishop of Ancyra, at a council in Tyre.

To defend his action, he wrote _Against Marcellus_, in which he accused Marcellus of being a Sabellian, too. Sabellius' heresy was (to borrow a modern term) modalism, the view that 'Father', 'Son' and 'Spirit' are mere titles, aspects, 'modes' of God, not in any real way distinct. He also accused Marcellus of adoptionism, another agreed heresy. Marcellus taught that the Son only became an aspect of the divine nature at the Incarnation, and that in the last day, Christ would hand over his kingdom to his Father.

This action would cast a long shadow over the next half-century. Time and again, bishops allied to Eusebius' way of thinking, or 'Eusebians', would re-affirm their opposition to that 'heretic' Marcellus and his 'Sabellianism'. This is a crucial dynamic for understanding where theological factions drew up their battle lines, and for what compromises were needed in order to get to 381.

Even the bishop of Alexandria wasn't immune from Eusebius' purge. Athanasius had vigorously defended his ally, Marcellus, at the council of Tyre in 335. Eusebius set about plotting his downfall. He dug up dirt. He accused Athanasius of using threats and bribes to get himself elected, and sending goons to beat up his political opponents. Once he'd found evidence of Athanasius meddling with the crucial Egyptian grain export that kept Rome fed, he had the emperor on side. Constantine convened a meeting in 336 and exiled him to the German frontier.

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Or at least, that's how Athanasius tells it. Athanasius loves a plot: at the time, alleging a conspiracy was a classic rhetorical technique for painting your enemies as heretics.

Eusebius was no stranger to rhetoric himself, and it's to his 337 best-seller, the _Life of Constantine_, that we owe our standard account of Constantine's reign. He regarded Empire and Church as allies in a joint mission, to unite the world under one government and one faith. To him, someone like Athanasius, constitutionally incapable of tolerating anyone who disagreed with him and willing to use gangster tactics to get his way, was a threat to this divine mission.

It's worth remembering that after Constantine died, Athanasius would be re-exiled by four more Roman emperors. In his lifetime, only Julian failed to exile Athanasius, and him only perhaps because he didn't have time in his whirlwind twenty-month reign. We also can't be sure how much influence Eusebius actually had in the expulsion of Athanasius and his allies: it coheres well enough with the emperor's anti-sectarian agenda that it might have happened with or without Eusebius' involvement.

Perhaps Athanasius was a brute. Still, the Roman Catholic Church manages to venerate both Eusebius and Athanasius as saints. This may seem like a contradiction. But perhaps an ability to tolerate contradiction is precisely the legacy of 381.

But we're not there yet. By 335, Eusebius had engineered the exile of Eustathius, Marcellus, and Athanasius. After Constantine died, he had to do it all over again, but by 339, he had persuaded his successor, Constantius, to re-assert his father's exiles of the three men. With the Empire once again split, Athanasius and Marcellus headed to Rome to re-group and re-think.

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From Rome, Athanasius and Marcellus were safe for now from Eusebius' clutches, but also relatively impotent. In this period of exile in the 340s, in an effort to claw back his reputation, Athanasius developed the polemic which still defines the standard history of the fourth century. He invented a cunning label for Eusebius and his cronies: he called them 'Arians'.

Eusebius rejected the label as ridiculous. Arius had been reconciled, and more to the point, had died in 336. For that matter, why would a bishop follow the teaching of a mere priest? Not only that, but the label ignored significant differences between Arius' and Eusebius' teaching. His verdict was clear: the label 'Arian' is a baseless slur, with no other purpose than to tar his reputation as a heretic.

He was right, of course. But like it or not, Athanasius' theory of an Arian conspiracy began to win adherents, not least Julian, the bishop of Rome. Julian called a council to exonerate Athanasius and Marcellus. When the Greeks refused to turn up, he called a local council anyway and vindicated the two men. In the face of Greek obstinacy, Julian wrote east, pleading the bishops to take the 'Arian' threat seriously.

In response, the easterners held a council in Antioch in 341, agreeing four creeds which powerfully condemned Marcellus' teaching, including the influential Dedication Creed. This includes assertions that Father, Son and Spirit are 'three in subsistence, one in agreement', that the Son was generated before time began, against Marcellus' teaching that the Father, Son and Spirit are aspects of God without division in subsistence, and that there only came to be a divine Son at his incarnation. They explicitly condemned Arius, Sabellius and Marcellus.

So the divisions grew deeper. Without an emperor to compel the bishops to come together, there may not have been much chance of a rapprochement. But even if there were to be such an emperor, who's to say that their settlement would have satisfied the bishops?

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Meanwhile, in the 340s and through the 350s, two further theological movements gathered steam: the homoians and the heterousians.

The homoians, perhaps tired of the squabbles between the Athanasian and Eusebian factions, determined to sidestep their petty debates altogether.

A key term of the theological disagreement was 'essence' or 'ousia'. Athanasius, in his lifelong battle to make sure Arius stayed dead, insisted that Father, Son and Spirit shared the same ousia. In contrast, Eusebius, with his anti-Sabellian polemic, needed to assert the real distinction between Father, Son and Spirit, and so asserted that each had a separate ousia. So the difference can be summed up as a counting problem. How many divine ousias are there? One or three?

The homoians claimed that both sides were mistaken, simply because they used the word 'ousia'. There is no mention of ousia in Scripture, so, they claimed, we have no basis for asserting it of God one way or the other. All we can truly say is that Father, Son and Spirit are distinct but somehow alike. Whereof we cannot speak, there must we remain silent.

This might have worked as a way forward, except that the heterousians provoked such a strong reaction that 'ousia'-talk was needed to refute them. Aetius, and his followed Eunomius, argued that since God is simple, and all generate things are divided, it follows that God is ingenerate. But the Son is generate: therefore Father and Son must be altogether unalike. They expressed this by saying that Father and Son are unlike in ousia. This teaching was swiftly branded 'neo-Arian', provoking a strong reaction. To counter the heterousian teaching, their opponents were forced to fight on their terms, and that meant using 'ousia'-talk.

Thus enters Basil of Caesarea. He argued that if we abandon 'ousia'-talk, we will have no way of saying that the Father and Son have anything in common at all, which makes a nonsense of the idea that the Son brings humanity knowledge of his Father. Without like essence, they might as well be two completely different Gods. Therefore we have to say at least that they have like essence -- 'homoiousia'. But without direct access to perfect knowledge of the invisible God, we're not in a position to judge that they have exactly the same essence, so he stopped short of agreeing with the 'homoousia' of the Nicene Creed which Athanasius so treasured.

Seeing the opportunity to make common cause against the homoians, Athanasius started to soften. He wrote an extremely charitable commentary on Basil's theology which emphasised their similarities and papered over their differences. Athanasius recognised that both he and Basil wanted to assert the unity of God while still preserving distinctions between Father, Son and Spirit. The two began to campaign against the homoian movement.

But Basil got there too late. In 359, the emperor Constantine II called a council in Constantinople, and in 360 it issued a homoian creed with full imperial backing. Any campaign against the homoians would have to take place sub rosa.

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In Athanasius' and Basil's long, slow campaign against homoianism, their weapon of choice was surprising: they dusted off the Nicene Creed of 325. Athanasius argued, against the homoians, that 'ousia'-talk, although not directly Scriptural, was essential in order to draw out the consequences of Scripture while ruling out Arian mis-interpretations.

Thus Nicaea, conceived as a one-off meant to clean up the Arian controversy, found a new life as the anti-homoian movement -- or perhaps you could call it the Nicene revival? -- rallied around it.

As the movement progressed, the formerly disagreeing bishops found ways to come together. An essential move was that made in Athanasius' _Antiochene Tome_ of 362. In it, he relented on his long opposition to there being three 'hypostases' or 'substances' in the Godhead.

'Hypostasis' had for a long time been used interchangeably with 'ousia'. However, Athanasius claimed that perhaps God could have three hypostases, but only one ousia, at the same time. In so doing, he wedged apart a sharp technical distinction between 'hypostasis' and 'ousia' which previously wouldn't have made sense. Logical or not, it enabled the Nicene revival to have its cake and eat it. God is both one in ousia, protecting against Arianism, and three in hypostasis, protecting against Sabellianism.

So the Nicene revival gained a new superpower: the power to use formerly synonymous terms to assert contradictions without blushing. This power to accept apparent contradiction as part of the unknowable mystery of God is perhaps the most important legacy of the period. Arguably, the church has been at its best when it has put aside the need to know everything, and embraced this spirit of tolerance, humility and faith.

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For much of the 360s and 370s, the homoian emperor Valens had ruled over the eastern part of the Empire, while his big brother, Valentinian, ruled the west. In the late 370s, Valentinian and then Valens died within quick succession of each other. Valentinian's twenty-year-old son, Gratian, was left to clear up the mess. In 379, Gratian delegated rule of the east to Theodosius, who was to implement a decisively different religious policy than his predecessor, Valens.

In 380, Theodosius issued an edict, saying that only those who agreed to the homoousios clause of the Nicene Creed could be considered 'catholic' Christians. The message was clear: the homoians were out, and the Nicenes were in.

In 381, he called a council to Constantinople, and it (probably) issued the revision of the 325 creed which is still used in various versions in all the world's largest Christian denominations. There would be no more revisions, and it would become, then as now, compulsory reading for all those preparing to don vestments.

One question is, why did the 381 creed differ in the ways it did from 325? Many of the differences, including the much-enlarged section on the Son, seem to have little controversial content: nobody was disputing that Jesus was born of the Virgin Mary, for example, though she makes her first appearance in the Creed in the 381 version. Some historians think this suggests that the 381 was based on a similar, but distinct creed from 325. This seems unlikely to me, given that about half the creed is in verbatim agreement with 325.

However, a couple of edits stand out. There are some clear signs of anti-Marcellianism: 'his \[the Son's] kingdom shall have no end', the Son is begotten of the Father 'before all ages'. Perhaps a clear emphasis on the eternal relationship between the Son and the Father was part of the diplomacy needed to get the Eusebian faction on-side.

The new details on the Holy Spirit are interesting too. They suggest a delicate compromise. Some bishops were reluctant to suppose that the Father and the Spirit have the same essence. On the other hand, others reckoned that they must share the same essence, given that they are equally deserving of worship. Thus the creed does not have a 'homoousios' clause for the Spirit, but does assert that the Spirit 'together with the Father and with the Son is worshipped and glorified'. With a spoonful of humility, both sides can be satisfied with that.

The revised Nicene Creed was the focus point, the distillation of a growing theological movement, formed by the various anti-homoian bishops finding a way to keep true to their own convictions while respecting each other's red lines.

As a result of the context of 325, Athanasius' relentless anti-Arian polemic which kept that movement alive, and the 'neo-Arian' heterousian movement, the new Nicene tradition insisted on the full co-equal divinity of Father, Son and Holy Spirit. This doctrine ensures Nicenes can affirm that Christ mediates true knowledge of the transcendent Godhead to humanity: the one who was born of Mary, suffered and died on the cross, was raised from the dead and ascended into heaven was true God from true God, of the same essence as his Father.

To satisfy the Eusebian strain, which defined itself by opposition to Marcellus, the Nicene tradition included a commitment to a robust distinction between Father, Son and Spirit, and to the eternity of the Son: begotten of the Father before all ages, his kingdom shall have no end. As a result, Nicenes inherited a way of thinking about God's action in the world, as instrinsically co-operative without being divided.

The biggest change between 325 and 381 was not the text, but what the text is used for. In 325, the Creed functioned to condemn Arius in order to heal the divisions his teachings had caused. In its second life, the Creed found an altogether new purpose: to serve as a common statement of orthodox faith. It started life as a way to define who was out. It ended up defining who was in.

Where was Athanasius? Consider that when Athanasius was appointed bishop in 328, he was relatively young for a bishop at thirty-five. That means that in 381, he would have been the ripe old age of eighty-eight. In fact, he didn't make it that far: he died in peace in the countryside outside his native Alexandria in 373. If he had seen the outcome of 381, he might have regarded his life project complete. Perhaps he knew that with the new generation of bishops, the tide was turning for good, and died in peace. Perhaps not. Either way, his compromises, and his beloved homoousios, have left a permanent mark on the church.

This is the legacy of 381. It is two-faced: any common statement of faith can be used to exclude. Indeed, in the late fourth century, both non-Nicene Christians and pagans found themselves the victims of increasing state-backed sectarian violence.

However, 381 also bears witness to the power of humility and faith. Once we stop grasping at perfect knowledge we cannot attain, we can begin to appreciate the mystery of God. This is one legacy I hope we can carry forward into our century.

