What happened 1,700 years ago in Nicaea – an interview with Prof. Henryk Pietras, PhD, SJ

I’m speaking with Prof. Dr. Henryk Pietras SJ (born 1954) – a patrologist and Byzantinist, lecturer at the Pontifical Gregorian University in Rome. Father Professor specializes in research on the origins of Christian culture (1st–5th century) and in editing – both in the original languages and in Polish translation – synodal documents and theological books of the ancient Church. Among other works, Professor Pietras is the author of the outstanding publication The Council of Nicaea 325 (first published in Polish in 2013; English edition in 2016, Italian in 2021; second, revised and expanded Polish edition in 2025).

In 2025, we mark the 1700th anniversary of the First Council of Nicaea, one of the most important events in the history of Christian theology and the development of Church doctrine. It is widely believed that this event was convened in 325 by Emperor Constantine the Great and represented a pivotal moment in the development of Trinitarian dogmas, especially with regard to clarifying the relationship between the Father, the Son, and the Holy Spirit. Furthermore, it is commonly stated that the Council of Nicaea not only condemned the Arian heresy but also established the fundamental doctrinal framework that remains the foundation of Catholic and Orthodox theology to this day. In the context of this anniversary, it is worth analyzing both the historical significance of the event and its theological legacy, which continues to shape dialogue among different branches of Christianity.

This interview is devoted to source-critical issues concerning the First Council of Nicaea (325 AD), one of the most important events in the history of Christianity. Professor Henryk Pietras SJ answers key questions regarding the available historical sources: which of them are considered the most reliable, what we actually know about the course of the council, and which issues remain in the realm of speculation. The conversation highlights the complexity of the work of an ancient historian—tracing the fate of medieval copies, critically analyzing their authenticity, and pointing out the limitations imposed by the intermingling of the few original documents with forgeries.

The interview also addresses the topic of the council’s iconography, as well as the influence of later accounts and legends on shaping the image of the event. The conversation includes themes such as the political and religious roles of Emperor Constantine, doctrinal issues (Arianism, the term “homoousios”), and the significance of the council for later Christian tradition. The interview provides a synthetic overview of the current state of research and serves as an inspiring guide through the complexities of the historical reconstruction of this pivotal council.

Professor, which historical sources concerning the First Council of Nicaea are currently considered the most reliable and widely accepted by scholars? To what extent can we rely on them when seeking accurate answers to key questions about the course and decisions of the Council? Please indicate which facts about the Council can be regarded as certain and well-documented, and which issues still remain the subject of scholarly disputes or speculation.

The primary historical sources about the Council of Nicaea are above all those accounts that are directly contemporary with the council itself, rather than those written a hundred years later. These include the “Life of Constantine” written by Eusebius of Caesarea, as well as a letter from Eusebius addressed to his church in Caesarea, sent shortly after the proceedings of the Nicene council. Also significant is the letter from Emperor Constantine, which—so it seems—was distributed to all the bishops at the close of the council, so they could take it home and show it to others. In this letter, the emperor expressed his satisfaction that the council had taken place.

In addition, the Nicene Creed (symbol of faith) and a set of 20 canons, which were voted on, adopted, and promulgated at the council, have been preserved in various sources.

Then, already 25 years later, there appears the work of Athanasius the Great titled “On the Decrees of the Council of Nicaea,” in which he presents his interpretation of the creed. However, this is not necessarily consistent with the original intention of the council participants, but rather Athanasius’s interpretation 25 years after the fact.

These are the main sources we have on this council. Later, further accounts concerning the council begin to appear, but these are already very elaborate and often contain legendary elements. We find them in the “Church Histories” written in the fifth century by Socrates Scholasticus, Sozomen, and Theodoret.

I have another question of a source-critical nature that has always interested me. In what form have the oldest sources concerning the First Council of Nicaea been preserved? Do we have only later copies, or have any originals of these documents survived somewhere?

No, all of these sources have survived only as medieval copies of earlier copies and as quotations in other works.

Copies of copies… Are we able to trace the path of these copies? Where is the oldest surviving copy located?

I don’t even know that. These texts are also cited by historians. However, from ancient times, not a single document has survived in its original form, except for stone inscriptions—that is simply impossible. The originals were created on papyrus, and those have long since been destroyed by the elements or even by mice, so no originals exist. The oldest manuscripts we possess date from the end of the first millennium. Occasionally, there is something from the 7th century, but that is rare. Generally, most manuscripts come from around the year 1000. So we can assume that the oldest copies of copies are about a thousand years old. Of course, this also depends on the particular text, since they are cited by various authors, but no original texts exist—that is certain.

I see. So it is not known exactly where to look for these oldest copies of copies.

That is, it is known where they are located. In the introduction to each edition of these works, there is information about which manuscripts are used and where they are kept. This is described in detail, with the specific libraries or archives indicated.

To sum up, in reality, we have a very limited number of sources concerning the First Council of Nicaea—in fact, one could say that there are extremely few of them?

In reality, what we have is what was established there—the creed and the canons. These are the documents that all the bishops took home with them and kept in their own archives. Later, some of them made copies, which were then further passed on in the form of subsequent copies.

Is there a real chance of discovering previously unknown documents concerning the First Council of Nicaea, for example in the Vatican Archives or other large manuscript collections?

No, there is no such possibility. The Council of Nicaea took place in 325, and the Vatican as an institution, as well as its archives, did not exist at that time.

Of course, I’m not referring to the originals, because—as we’ve already established—there is no reason to expect that they have survived anywhere. The question concerns possible copies—manuscript copies of these documents. Do contemporary archival studies still bring significant discoveries in this area, or should we rather assume that most of the surviving sources have already been identified?

All known copies have already been identified. Even if, for example, another copy of one of these letters were to be found in some library, it would not change anything—it would simply be another copy of an already known document. There is virtually no chance that an unknown document concerning the Council of Nicaea might be discovered, as since the 5th century it has been recognized as an ecumenical council and the most important for the Church. This is extremely unlikely. Even if some text of marginal significance had survived somewhere, for example as a book cover (because sometimes old parchments are discovered in this way), in this case, I consider it excluded. Besides, I cannot even imagine what that could be, since the sources speak only of the creed and the 20 canons. So, there is nothing more to look for.

In the context of analyzing historical sources concerning the First Council of Nicaea, we focus on written sources. However, a question comes to mind regarding the role of icons depicting this event—can such representations be considered a reliable source of information about the location and course of the Council? Is there any justification for considering the iconography related to the Council of Nicaea as historical evidence of the events of 325, or should it be regarded solely as artistic and religious material?

No, there is no such justification. All the icons related to the Council of Nicaea, of which there are very many—especially in the East—are legendary in character and were created much later. As far as I know, the oldest of them date at most from the end of the first millennium, but none of them constitute a historical source. These icons present rather the imaginations that arose several centuries after the events and are subordinated to certain ideas—for example, they often depict the emperor in the center, surrounded by bishops.

In the Middle Ages, it was commonly assumed that certain individuals who were allegedly condemned were present at the council, and that is why on some icons you can see them lying at the emperor’s feet. However, this has no confirmation in historical sources. Even in the polychrome decoration of the Lateran Baptistery, which was created in the Middle Ages, there is a scene known from the church history of Socrates Scholasticus—namely, that the bishops addressed so many petitions to the emperor that he ordered them all to be collected and burned, not wanting to deal with them.

Iconography cannot help us reconstruct the actual course of the Council of Nicaea. It is above all a means of expression reflecting the ideas and intentions of the creators, not historical reality. Icons show what the artist thought, not what really happened.

In the second, most recent edition of your work concerning the Council of Nicaea, there appears a hypothesis about the possible forgery of some post-conciliar documents, which was not included in the 2013 publication. Could you elaborate on this issue?

For over 20 years, I have been studying the Council of Nicaea. My first article on this subject appeared in 2000. The book was not the first work—I began working on this topic even before 2000: first came the initial article, then a series of others, quite a few in total. In 2008, I wrote an article about the aforementioned forgeries. Eventually, I decided to write a book (and this edition discusses the forgeries), which was published in Polish in 2013 and later in other languages as well. This year, a new edition appeared in Polish.

As for the forgeries, they also concern some post-conciliar letters. In the surviving church histories from the 5th century, there are several letters: the council’s letter to the Church in Alexandria, the emperor’s letter to the Church of Egypt and Libya, and the emperor’s letter to all the churches. The last of these letters has also survived in the “Life of Constantine” written by Eusebius, at most two years after the emperor’s death, that is, in 337 or 338. There is no reason to question its authenticity, because it was written very close to Constantine’s lifetime. If it were inauthentic, it would have been questioned already in antiquity, whereas all ancient historians acknowledge and comment on it.

However, the letters—the emperor’s letter to Alexandria, Egypt, and Libya, as well as the council’s letter to Egypt—I consider inauthentic. They contain many anachronisms and information that no one could have known in 325. For example, all known testimonies from that time speak of 240–250 participants in the council, while one of these letters, which I consider to be forgeries, already gives the number of 300 participants—a figure that appeared only in the 360s and was later rounded up to 318. Furthermore, no conciliar canon or contemporary testimony—whether from Eusebius’s letter or the works of Athanasius—mentions Arius. Yet, in these letters, there is information that Arius was condemned and exiled, which only appeared in the 360s, not earlier.

In short, these letters could not have been written earlier. In my book, in the chapter on forgeries (and briefly in the first edition as well), I analyze these hypotheses in detail and present all the arguments, pointing out anachronisms that would have been unthinkable in 325 but are typical of the 370s. At that time, after the death of Athanasius—who never saw or quoted these letters—his successor had many difficulties and returned to Alexandria only around 378. It seems that it was then that these letters appeared, though this is a very detailed issue that I analyze in the book.

When comparing these documents, it is clear that they add nothing new regarding the Council of Nicaea, so there is no point in dwelling on them.

During our first meeting in Rome, in the winter of 2025, you mentioned a tsunami whose epicenter was near Crete. You also mentioned that the tsunami wave struck the southern coasts of the Mediterranean most strongly, particularly Alexandria. Could you remind us why this natural disaster interested you in the context of your work on the new edition of the book “The Council of Nicaea (325): Religious and Political Context, Documents, Commentaries”?

This event took place forty years after the Council of Nicaea, so it is not directly related to it, but it remains very interesting—the mention of the tsunami is particularly important as one of the arguments confirming the anachronism of certain forged letters and documents. These texts contain references to the geographical situation after the tsunami, although they supposedly were written before this event. This is exactly what I wanted to highlight.

The historian Marcellinus wrote that in Alexandria, ships were thrown by the tsunami wave as far as two kilometers inland, and Libya suffered the most—the impact there was the greatest, entire cities were destroyed, and the landscape changed significantly. As a result, new geographical names appeared, which are found in those letters, even though they could not have existed at the time of the Council of Nicaea, having only arisen after the disaster.

There are no direct mentions of the tsunami in the letters themselves, but they use place names and organizational terms that only came into use after this event. I must admit that when I was working on the first edition of my book, I was not yet aware of this—I only discovered this issue in recent years.

Oh, that’s very interesting! Now, let’s analyze the socio-religious context of the Council. What was the organization of the Church like at the beginning of the 4th century? What were the main challenges? What about the issue of religious persecutions and the development of doctrines and articles of faith? To what extent did doctrinal and organizational order matter to Constantine as the ruler of the Roman Empire?

This context is extremely important. The Council was convened by the emperor after he had achieved sole rule by defeating all his rivals. He became the sole ruler of the empire, which only happened on September 18, 324, after the final battle with Licinius. From that moment, Constantine ruled alone and wanted to celebrate this significant event. In the surviving Syriac copy of the emperor’s invitation to the council—originally convened in Ancyra and later moved to Nicaea—we read that Constantine invited the bishops to a council which was to begin on June 19, 325, on the occasion of the 20th anniversary of his reign (he had been proclaimed emperor by the army on July 25, 306).

Celebrating round anniversaries of one’s reign was a customary practice of emperors, and so Constantine, after uniting the empire politically, also wanted to use the Church and Christianity to strengthen the unity of the state through the unity of the Church. This was hindered by the existing schisms—especially two major ones that had appeared at the beginning of the fourth century during the persecutions under Diocletian: Donatism in Africa and Melitianism in Egypt. Both movements gathered Christians who considered themselves the only “pure” ones in the Church and did not want to have anything to do with those who, after penance, returned to the community—especially with apostates and those who remarried after divorce. They believed that bishops and clergy who admitted such believers to communion were unworthy of their office, which led to significant divisions in the Church, first in Africa and then also in Egypt.

These two schisms were very important to the emperor. Even earlier, as ruler of the western part of the empire, he had tried to resolve the problem of Donatism in Africa. There, the dispute concerned the election of the bishop of Carthage: the “pure” group chose Donatus, questioning the election of Caecilian because it had been carried out by those who accepted penitents back into the Church. This movement also had a national-liberation aspect: the Roman Church was seen by the local population as the “occupier’s” church, whereas Donatism was perceived as the native community. In the fourth century, these divisions were very pronounced.

We know about these schisms, among other sources, from the “Life of Constantine” written by Eusebius soon after the emperor’s death. It is emphasized there that the breaking of church unity was a great misfortune that Constantine wanted to overcome. This is also reflected in the canons of the Council of Nicaea: for the first time in history, there was not a single condemnation or exclusion of anyone. One canon is devoted to schismatics, and it speaks not of excluding them from the Church, but of the conditions for their readmission to the community. Canon 19, concerning heretics—especially the followers of Paul of Samosata—also regulates the issue of readmission to the Church, not exclusion.

The emperor was primarily concerned with uniting the Church, as this was meant to serve the unity of the empire. Of the many schisms, he paid special attention to these two; others were of lesser importance to him.

Was the emperor therefore interested in unifying Christian doctrine?

No, I don’t think so. Constantine was not concerned with doctrinal unity. His main goal was to unify the Church as an institution, so that there would be one Church, regardless of differences in beliefs. For him, the unity of the Church was more important than resolving doctrinal disputes. He believed that the Church could be united despite internal differences, as this was a typically Roman approach.

As a Roman, he did not think in terms of orthodoxy—this concept did not exist in Roman religion. The point was simply that all religions should cooperate in the interest of the state, and that everyone should pray to their gods for the prosperity of the empire. Constantine imagined that if the Church was united, without factions fighting each other and excluding one another from communion, then prayers for the unity and prosperity of the empire would be more effective. That is what he wanted to achieve.

At the beginning of the 4th century, Christianity was still a relatively young religion and—as you mentioned—in a sense, it was still taking shape. There were no means of rapid communication such as today’s emails or telephones, which would allow the new faith to spread instantly, so its development required both time and overcoming spatial barriers. In this context, I would like to ask: how numerous and how strong were the Christian communities during this period? What made Christianity develop at such an impressive rate? What was the reason that Emperor Constantine became interested in this religion at all? Were Christian communities truly strong and expansive enough to justify the emperor’s involvement—both in terms of his attention and his later financial support for Christianity?

In my opinion, the situation was such that Christianity at that time had no real competition when it came to community organization. Roman religions functioned on the basis of complete autonomy—each temple conducted its own cult independently of the others. For example, between the temple of Jupiter and the temple of Cybele, even if they were only a short distance apart, there were no connections or cooperation. Each cult existed separately, and the only unifying element was participation in the state liturgy, that is, making sacrifices together for the prosperity of the empire.

Meanwhile, Christianity stood out because of its strong sense of unity—regardless of whether a Christian community was in Jerusalem, Rome, or Antioch, it belonged to the same Church. I think it was precisely this potential for unity, despite the great dispersion and small size of individual communities, that could have been attractive to Constantine. If all these communities began to work together for the unity of the empire, it could have real effects, whereas other pagan cults lacked such structures.

Christian communities from the very beginning formed a certain organizational structure—bishops were at their head. Relatively quickly, within the provinces of the empire, the bishop of the capital city began to be treated as a metropolitan, presiding over the bishops of the entire province, which provided an additional integrating element. Moreover, communion between Christian churches, both within a single province and between provinces, was constantly maintained. An example of this was the Eucharistic custom—when a new metropolitan bishop was elected, during his first Mass he consecrated breads, which were then sent to all neighboring bishops. The bishops of those metropolises would receive Communion not from their own gifts, but precisely from those sent by the newly elected metropolitan. All this testifies to the unique, strong bond and structure of the Christian Church, which was missing in pagan religions.

This is how the network of Christian communities was shaped, existing even despite the fact that—as some researchers claim, perhaps rightly—Christians at that time constituted only about 3% of the population. It is worth noting that at the beginning of the fourth century, the Church did not yet include rural areas—Christianity was a typically urban religion, and only cities had churches. Rural areas were left out at that time; only at the end of the fourth century did missionaries begin to preach the Gospel in the countryside as well.

At this stage, then, Christianity was an urban religion, but it was characterized by extraordinary spiritual unity—the same believers, professing the same principles, were present in different cities. I think that it was precisely this element of unity that could have been attractive to the emperors and the reason for their support of Christianity, as the Church thus became a factor integrating society. At least, this is how it appears from my perspective and on the basis of my knowledge.

That is a very interesting concept. However, I am still intrigued by the relatively small number of Christians at the beginning of the 4th century, which—despite its modest size—translated into an extraordinary strength of influence and an ability to exert impact on their surroundings.

Unfortunately, we do not have precise statistical data on the number of Christians during this period. However, we can draw conclusions based on the number of bishops present at various synods—at some meetings there were 100, at others 150, 200, or even 300 bishops. This shows that Christian communities did indeed exist, although they were relatively few in number. It is also worth remembering that a bishop at that time was not the head of a diocese comprising hundreds of thousands of believers, as is the case today. In those times, churches were small—often consisting of just a few dozen, at most a few hundred, people.

The figure of Emperor Constantine remains an interesting topic—a pagan who convened the Council and participated in it as the first ruler in history to do so. According to traditional knowledge, Constantine was baptized only shortly before his death in 337. Was he actually baptized? How reliable is the information about Constantine’s baptism, which essentially comes from a single source—Eusebius of Caesarea? How should we assess the likelihood that the baptism really took place, especially considering that the emperor’s funeral ceremony was largely pagan in character, with only a few Christian elements?

According to Eusebius of Caesarea, Constantine’s baptism did indeed take place, but it occurred only a few days before his death in 337. There are several records on this subject. The baptism was administered by Bishop Eusebius of Nicomedia, who was serving in that position at the time. Constantine’s funeral itself followed the traditional, established imperial ritual, which was not unusual. The emperor’s funeral ceremonies were strictly regulated by various customs and traditions, which could not be violated—the imperial dignity did not allow for it.

If there were any Christian elements, they were probably limited to symbolic gestures, such as a bishop making the sign of the cross over the coffin. I do not think there was anything more than that. Anyway, I know little about the details of Christian funerals in antiquity.

The emperor himself wished to be buried in the Church of the Holy Apostles, which he built in Constantinople. He brought there the relics, or supposed relics, of all twelve apostles, for whom twelve sarcophagi were prepared, and in the central place was the sarcophagus intended for himself. For this reason, he was later called the “thirteenth apostle.” Some, perhaps rightly, ironically remarked that he considered himself more important than the apostles, wanting to be buried in their center, in the manner of Christ occupying the central place at the Last Supper.

What his real intentions were is hard to determine today, but the fact is that he was buried there—this is beyond any doubt.

In which historical sources can we find information regarding Constantine’s wish to be buried in a particular way and specifically in the Church of the Holy Apostles? Can we point to specific texts that confirm his will concerning the place and nature of his burial?

Information on this subject can be found in the “Life of Constantine.” This is the oldest and essentially the only source that describes Constantine’s wish regarding the manner and place of his burial. Later accounts are based precisely on this work.

Let’s return to the subject of the Council itself. What other organizational and theological issues were discussed, and what decisions and resolutions were made there?

Apart from the issue of the lack of unity within the Church, a serious matter was the question of determining the date of Easter. Christians could not agree on when to celebrate this most important feast. In the East, especially in Syria and Palestine, as well as further east, people followed the Jewish tradition and celebrated Passover together with the Jews, regardless of which day of the week it fell on. However, the rest of the Church followed the tradition derived from St. Paul the Apostle, according to which Easter was to be celebrated on Sunday, the day after the Sabbath. This was based on a developed theology that the resurrection of Christ was an overcoming of the order of creation—after the seven days of creation comes the eighth day, identified with the first day of the week, when the resurrection took place.

The West, Constantinople, Asia as a province, and Egypt—all celebrated Easter on Sunday. Meanwhile, Judeo-Christians and others under their influence in the East were already a clear minority. Nevertheless, this division existed within the same empire and was a significant problem for the emperor, because he wanted the common celebration to be a visible sign of the unity of the Church, and thus also of the unity of the state. Doctrinal matters interested the emperor much less, mainly because he was not competent in them—after all, he was not a Christian, he was not baptized. He was the ruler of the empire, concerned with its unity, and he subordinated his actions to this aim.

What about Arianism? According to common and often repeated opinion, this issue is considered one of the most important topics discussed during the First Council of Nicaea. Was Arianism really at the center of the council’s deliberations, or has its role been exaggerated in later tradition and historical interpretation? What place did this dispute actually occupy in the course of the Council?

In my opinion, the issue of Arianism was not taken into account by the emperor when convening the council at all, as he considered it too trivial. Just before the council, only two years earlier, a dispute broke out in Egypt between the bishop of Alexandria, Alexander, and the presbyter Arius. Indeed, Arius, in his reflections, had come to the conclusion that the divine Logos incarnate, that is, Jesus Christ, could not be truly God. For if he were truly God, his obedience to the Father would be a fiction, a mere appearance. On the other hand, if his obedience was real, it would mean that his will could be changeable, and thus Arius questioned the divinity of Christ.

Events unfolded quickly: the bishop asked Arius to present his profession of faith in writing. Arius did so, and his statement was signed, in addition to himself, by twelve other clergymen, including two bishops. Then, at a synod in Alexandria—I think it was around the year 323, though some move it as early as 320—they were expelled from the Church, excommunicated.

The matter could have ended there, if not for the intervention of the emperor, who wrote a letter to them, in which he rebuked both Alexander and Arius. In my book I quote this letter—in both the first and second editions—in which the emperor accuses them of quarreling over unimportant matters, claiming these are trivial issues of no significance for the unity of the Church, and orders them to reconcile as soon as possible and not bring shame. This letter reached Alexandria in late autumn of 324, delivered by Hosius of Corduba, a bishop and adviser to Constantine, who was sent by the emperor.

Unfortunately, Bishop Alexander remained steadfast and had no intention of lifting the excommunication. As a result, Arius appealed to his friendly bishops, which caused considerable commotion, since both he and Bishop Alexander sent numerous letters to other bishops, informing them of the situation and presenting their own positions—Alexander warning against the heretical theories advocated by Arius.

The council had already been called—to celebrate the anniversary of the emperor’s reign and to solemnly announce universal peace in the empire—regardless of the dispute between Arius and Alexander, but thanks to this correspondence, many bishops at the council knew about it. The topic certainly came up in the council’s corridors, and it may be assumed that in formulating the creed, efforts were made to compose it in such a way that it would leave no room for ambiguity regarding the acceptance or rejection of the divinity of Jesus Christ. Arian views must therefore have been present in the background of the proceedings, even though they were not explicitly recorded in the council’s documents.

Are we able today to determine which theological tradition lies behind the term homoousios included in the creed?

One thing is certain: according to the only source we have on this subject, it was the emperor himself who, in his wisdom, deigned to suggest this term. Where did he get it from? No one knows. He was not knowledgeable in theology, so he didn’t know that the term was used by heretics. He simply didn’t know this. Perhaps he suggested it because the term also had a common meaning, so to speak, of descending kinship. That is, children are consubstantial (homoousios) with their parents. In this sense, they are of the same kind, the same nature.

And to make it even easier, the emperor himself considered himself—and rightly so—the son of a god. His father, Constantius Chlorus, after his death in 306, was recognized as a god by the Roman Senate and by Constantine himself. In fact, a whole series of coins was minted in honor of this god Constantius, a temple was built, and offerings were made in accordance with all the rules of Roman religion. So Constantine might have thought: “What’s the issue here about Jesus being the true Son of God? I am a true son of a god, because I am from my father, who is a god.” I don’t know if that’s exactly how it was, but it seems probable to me, because none of the present Fathers could have suggested such a term, as no one was using it.

I have a question—a digression in the context of our conversation. From which year do the coins mentioned by the professor date? Have any examples of them survived to the present day?

As far as I remember, the last coin of this type dates from the year 318. A few specimens have survived.

What were the actual lines of division among the participants of the Council of Nicaea, and how did the disputes between conservative and progressive factions influence the development of doctrine and the final formulation of the Nicene Creed?

Indeed, accounts of the Council of Nicaea indicate that there were clear divisions among the participants. For example, Eusebius, in a letter written a month or two after the Council, repeatedly refers to the proceedings using the terms “we” and “they,” suggesting the existence of opposing groups. This raises the question: whom did he mean by these terms—who were “we” and who were “they”?

A similar distinction also appears in the statements of other participants of the Council: “they did this,” “we did that.” However, it does not seem justified to identify these groups directly with the Arians and their opponents, since there were no representatives of Arianism in the strict sense at the Council. The two bishops who had signed Arius’s letter had already been condemned in Alexandria. According to the church law in force at the time, excommunicated persons were not allowed to participate in synods—they could only be rehabilitated by their own church where they had been condemned.

Therefore, there could not have been representatives of Arius’s circle present at the Council of Nicaea, because under church law at the time, excommunicated individuals, like the two bishops connected with Arius, were not permitted to participate in a synod until they had been rehabilitated in their own church. So the question remains: whom did Eusebius and other council participants mean when speaking of “us” and “them”?

It appears that researchers’ recent observation is accurate: as in any large assembly, the Council included bishops with both more conservative and more progressive approaches. Thus, in the work on the new creed, two tendencies emerged: the conservatives advocated for preserving traditional, biblical formulations, which, however, were general and ambiguous; the other group understood that the principles of faith needed to be defined more precisely. Hence arose the need to introduce the concept of “homoousios”—“consubstantial,” which, as is generally accepted, was suggested by the emperor. This term was carefully explained to avoid misunderstandings related to its philosophical and non-biblical character; it was emphasized that it did not refer to corporeality, but rather expressed a spiritual unity worthy of God.

Despite the introduction of this concept, for the next 25 years there is no evidence that anyone invoked the Nicene Creed. Only around the year 352, thanks to Athanasius, did the process of explaining and popularizing the Nicene Creed and terms like “homoousios” and “from the substance of the Father” begin. There was, however, strong resistance to the introduction of new concepts, mainly due to attachment to traditional, biblical formulas and reluctance to introduce philosophical terminology (such as “ousia,” “hypostasis”) into the creed.

As a consequence, for a long time, the so-called Homoean creed (“homoios”—“similar”), according to which the Son was “in all things similar to the Father,” enjoyed great popularity. This solution seemed safer and gained the support of Emperor Constantius II, who even led to the prohibition of ambiguous philosophical terms at the synod in Constantinople in 360.

The change came only under Emperor Theodosius, who in 380, wishing to end the endless debates, decreed that only the Nicene Creed would be valid throughout the empire. At that point, the majority of bishops complied with the emperor’s will, especially as church funding also depended on the decisions of the authorities.

The so-called Cappadocian Fathers—Basil the Great, Gregory of Nyssa, and Gregory of Nazianzus—contributed to the dissemination and reinterpretation of the concept of “homoousios.” Starting in the 370s, they proposed the distinction between “one ousia” (essence) and “three hypostases” (persons) in the Holy Trinity, which in time was accepted and spread throughout the Church. Their rich literary legacy helped to solidify this understanding, though the process took many decades.

Ultimately, the creed from the Council of Nicaea, with the term “homoousios,” was confirmed as the sole and binding confession for the entire Church at the Council of Ephesus in 431, and later reaffirmed at the Council of Chalcedon in 451. In this way, the so-called Nicene orthodoxy became the foundation of Christian doctrine.

At what point does Arian theology definitively diverge from the main current of Christian orthodoxy? During the Council of Nicaea, was Arius’s theology regarded as heretical by the majority of bishops?

Arian theology diverged from the faith of the Church from the very outset—Arius’s explanations departed from Church teaching, since the Church believed that Jesus Christ is God. Arius, on the other hand, said, “He is not,” because he could not understand how God could be obedient. Others responded, “We also do not understand, but the faith of the Church is that we believe He is the Son of God.” It did not depend on whether someone understood this or not.

Arius, however, insisted that things must be as he understood them, and for this reason, he was excluded from the Church. No one in the Church fully understood this mystery, but no one insisted on their own lack of understanding against the faith of the Church. Already in Arius’s first letter, it is clear that his views deviated from the faith of the Church. The notion, however, that there was a great Arian theological opposition at that time is a construct—it is a mystification created by Athanasius of Alexandria. Only from about 352—and according to some, from as early as 340—can we speak of Arianism as a collective term for those who rejected the divinity of Christ as described in the Nicene Creed. By then, Arius was already dead, as were all his immediate followers.

Arius was merely a starting point—his views on Christ’s divinity became the basis for labeling as “Arian” anyone who did not agree with the Nicene homoousios. It did not matter whether someone had heard of Arius or knew his teachings. For example, the Goths were called Arians because they adopted their own creed—the Constantinopolitan one from 360—which excluded the legitimacy of using the term ousia. Thus, they were labeled “Arians” and accused of denying the divinity of the Son of God, even though they actually believed in His divinity—they just did not want to use the same terminology as the Nicenes.

Arianism thus became a catch-all term, introduced to make it easier to discredit opponents. Athanasius strongly promoted this approach: either one agreed with the Nicene Creed, or one was an Arian. He did not use the word “Arians,” but called them “maniacs of Arius,” in Greek ariomanitai. This term entered history, and later, reading these records anachronistically, people began to think that Arianism began with Arius. In reality, however, the denial of Christ’s divinity did not necessarily begin with Arius—such views had already been present in various earlier heresies. All supporters of such views and opponents of the Nicene Council began to be called Arians only in the middle of the fourth century.

Further attempts at reconciliation undertaken by emperors brought little result. Finally, Emperor Theodosius decided to put an end to these disputes. He tried, in 383, to convene a sort of synod of all heresiarchs to achieve unity in the imperial Church, but this had no effect. Ultimately, Nicene orthodoxy, supported by the emperors, prevailed, and the entire Church adopted the creed emphasizing the divinity of Jesus Christ.

And to conclude our conversation—perhaps the most important question—what significance does the Council of Nicaea have today for contemporary Christianity and for ecumenical dialogue? In what ways do the decisions and the creed adopted at this council continue to shape today’s Christian traditions and identities?

The Council of Nicaea became a symbol of orthodoxy, primarily because its decisions were widely discussed for a long time and eventually gained imperial authority. It was the first council convened by the emperor, with the emperor personally present from beginning to end. Previously, Constantine had convened synods but did not participate in them personally. This time, he chose to solemnly open the council with his own speech, to take an active part in the deliberations, and to close the council—giving the event special significance.

Imperial authority thus became linked with the Council of Nicaea, and its decisions were promulgated by subsequent emperors as well. The following great councils considered pillars of orthodoxy—the Council of Ephesus (431) and the Council of Chalcedon (451)—also affirmed the significance of the Council of Nicaea, which was granted the status of a model of orthodoxy. It became a symbol of orthodoxy and the unity of the Church. In Eastern Churches, especially those of the Byzantine Orthodox tradition, the feast of the Council of Nicaea is celebrated. In some Eastern Churches that separated from the imperial tradition—such as the Armenian or Ethiopian Churches—the feast of the Council of Nicaea is celebrated even several times a year. Thus, the Council became an unquestioned sign of unity and orthodoxy in the Eastern traditions.

The Council’s role in establishing a single date for the celebration of Easter is also emphasized. In jubilee years, this topic often arises—there are voices that, by continuing the intention of Emperor Constantine and the Council of Nicaea, the Church could finally arrive at a common date for celebrating Easter. This would be a beautiful achievement, although—due to deeply rooted traditional differences—I personally think it is unfortunately unlikely.

The significance of the Council of Nicaea lies above all in the enormous effort put into defining the faith in the divinity of Jesus Christ, promulgating it, and having it accepted by all Christian Churches—both those in unity with Rome and those who have separated from that unity. All Churches use a creed that traces its roots back to that formulated at Nicaea and refer to it, which makes the Council of Nicaea a unique sign of the unity of Christianity. This, in my view, is its most important significance.

I sincerely thank you for sharing such extensive knowledge, for an inspiring and extremely interesting conversation, as well as for your kindness and the time you devoted.

Magdalena Czechowska