Who Will Remind the Pope of Arius and the Arians?

The spiritual leader of the Catholic world, Pope Leo XIV, is in Turkey today… For three days, he will hold meetings in Ankara, Istanbul, and Nicaea, then move on to Beirut. At the center of the visit is a single event: the 1700th anniversary of the Council of Nicaea. On Friday, he will descend to the ruins of the Basilica of Saint Neophytos, silently resting beneath the waters of Lake Iznik, and lead a service among the stones blended into the memory of the water.

As this scene is presented to the world today, another name, unspoken by anyone, moves among those submerged stones: Arius… So, in the files prepared to brief the Pope about Nicaea, is there any mention of that great Libyan sage and the Arians who followed him? Does anyone remember that the storm that broke out in Nicaea 1,700 years ago touched not only the Christian world, but also one of the deep fault lines of Islamic history?

Between Monotheism and the Trinity: Nicaea

The Council of Nicaea is often portrayed in most historical accounts as a dry theological dispute. Yet at its heart was not a minor “difference of interpretation” within the church, but a crisis exploding at the very center of the great reckoning between tawhid (monotheism) and the Trinity.

On one side stood Arius, the ascetic and contemplative sage nurtured by Libya… On the other was Athanasius of Alexandria. Arius maintained that Jesus (peace be upon him) was a created servant, the word and messenger of God. Jesus is not God; he is a human being created by God, who prostrates before Him. Athanasius, on the other hand, asserted that Jesus was the “eternal Son of the same essence as the Father.” The issue laid out on the table in Nicaea was the life-and-death struggle between these two assertions.

The outcome of the council was not determined by divine revelation but by the politics of the time. Emperor Constantine, who still bore the remnants of pagan traditions, took sides with Athanasius; the doctrine of the Trinity was elevated to the official teaching of the empire. But history is not a one-act play. That same Constantine soon leaned toward Arius’s belief and ended his life with a Christological understanding rooted in monotheism. His son, Constantius II, who succeeded him on the throne, would go even further, personally mobilizing to spread the creed of Arius throughout the empire.

Today, the absence of icons and figures in some old churches in Istanbul is not merely an aesthetic choice or a reflection of “Byzantine taste”; it is the silent memory of the Arian legacy etched into the stones. Those scenes where icons were scraped away and faces erased—but shadows remained on the walls—are architectural echoes of the unending tension between monotheism and the Trinity.

Iconoclasts and Iconodules in Istanbul

For centuries, Istanbul was besieged not only by political armies, but also by creeds. Between 700 and 900 AD, the fiercest debate in Byzantium unfolded between iconoclasts and iconodules. In 726, Emperor Leo III deemed icons a continuation of idolatry and ordered the removal of all icons from churches. This “iconoclasm” was not merely a war against images—it was also a delayed echo of the Arian monotheistic tradition, a protest rising from within Christianity itself.

In the middle of the century, Empress Theodora rose to power after her husband’s death and reinstated icons in the churches; this time, the iconodules had the power of the state behind them. However, this ebb and flow did not fully subside until the Muslim conquest of Istanbul. For the real issue was not whether a wall should be adorned, but how to define the boundaries between the conception of God, the consciousness of servitude, and the visible and the invisible.

In 336, the ideas of the Libyan Arius—who was martyred where Hagia Sophia now stands—eventually evolved into a sect labeled “Arianism.” Constantine, the founder of the city, embraced Arius’s teachings in the last two years of his life and exiled some Trinitarian priests. His successor, Constantius II, went even further to transform Arianism into the official creed of the empire.

As the great Andalusian scholar Ibn Hazm noted in al-Fasl, the mere fact that the first two emperors of Byzantium leaned toward monotheism is enough to demonstrate how deeply Arian—or monotheistic—currents left their mark on the history of Istanbul and Anatolia.

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Constantius II: The Monotheistic Wave in Rome

After the death of Constantine the Great in 337, the Roman Empire was divided among his three sons. The western territories were given to Constantine II, the central regions (Italy–North Africa) to Constans, and the eastern and most powerful portion to Constantius II. Constantinople, Anatolia, Syria, Palestine, Egypt, and the Balkans came under his rule. While his brothers leaned toward the Trinitarian stance, Constantius II joined the Arian interpretation and embraced the monotheistic belief that regarded Jesus as the servant and messenger of God.

At the center of his political mindset was a fundamental idea: what upholds the laws is not the sword, but faith and conscience in the heart. He sought to eliminate oppression and false religious understandings by inviting people to seek the truth sincerely, not by force. For this reason, Muslim historians refer to him as “the Roman emperor closest to Islam.” He tried to base state authority not on the Trinitarian theology that claimed “Jesus is divine,” but on a Christian understanding closer to tawhid.

He effectively crossed out the Trinitarian decisions imposed by his father Constantine at the Council of Nicaea in 325. At the councils he convened in 350, he had the rulings of Nicaea reexamined; he maintained the same stance at the Milan meeting in 355. As a result, the doctrine of the Trinity suffered a significant blow on the imperial stage, and Arian clergy and preachers found a space in which they could breathe. The Indian Theophilos’s ability to preach monotheism in Abyssinia, the islands of the Indian Ocean, and the Arabian Peninsula was a direct consequence of this political patronage.

By the time Constantius II died in 361, Arianism had become a living faith throughout the Roman realm stretching from east to west—expressed in the people’s language, worship, and prayers. Jerome, the translator of the Holy Bible into Latin, recorded this scene when he declared: “The world is full of Arianism.” But the emperor who followed, Julian the Apostate, completely rejected Christianity and tried to resurrect ancient paganism; later, Emperor Theodosius launched a harsh purge of the Arians to institutionalize the Trinity. Churches were shut down, their properties confiscated, clergy exiled, and books burned.

Yet they could not erase either the words of Maris of Chalcedon—“Praise be to God that my eyes were blinded so I was spared from seeing Jesus as a god”—nor the legacy of tawhid spread among the Gothic tribes by Ulfilas. Arius’s words were few, but his cause was profound: “Jesus is a servant created by God; He is His word and His spirit, but He is not God.” Centuries later, when the verse of the Qur’an confirmed this truth—“The Messiah, son of Mary, is only a messenger of God…” (Surah An-Nisa, 4:171)—another link in the chain of history fell into place.

This is precisely why Muslim historians interpret Arius’s struggle for monotheism as a threshold that prepared the ground for the emergence of Islam. This creed—spreading within and beyond Rome, from Abyssinia to Arabia, from the lands of the Goths to Central Asia—made it easier for hearts to accept tawhid when Islam arrived.

The Memory of Stones: The Three Lives of Hagia Sophia

While the political face of this wave of tawhid appeared in Constantius II, its architectural and symbolic face took shape in the earliest incarnation of Hagia Sophia. Before today’s Hagia Sophia, the first grand basilica known as the “Megale Ekklesia” or “Great Church” was built around 360 AD during the reign of Constantius II, near where the Basilica Cistern stands today. It was the first major temple in the imperial capital after Christianity had been declared the official religion of Rome.

This structure was destroyed during the political and religious unrest of 404. In its place, Theodosius II commissioned a new church in 415, this time on the site of today’s Hagia Sophia. From 430 onward, the structure was named “Hagia Sophia,” meaning “Holy Wisdom of God.” During the Nika Revolt of 532, the second Hagia Sophia was also consumed by flames.

On February 23, 532, Emperor Justinian ordered the construction of the third and current Hagia Sophia, appointing Anthemios of Tralles and Isidoros of Miletus as architects. The stones carried by tens of thousands of workers over five years came together in a sanctuary that opened on December 27, 537. Thus, the line stretching from the first church erected in the era of Constantius II to Justinian’s Hagia Sophia became not only a thread of architectural continuity, but also a history carved in stone—of the centuries-long tension between tawhid and the Trinity within Rome.

The Western Face of the Monotheistic Wave: The Visigoths

At the same time, a similar stir was taking place in the north of Rome. The Germanic Visigoths, thanks to the archbishop Yūfīlās (Wulfila), adopted the Arian monotheistic faith in the 4th century. This belief—that Jesus was not God, but a servant and messenger created by God—was in inevitable conflict with the Trinitarian doctrine of Rome. As a result, the Arians suffered Roman persecution for centuries.

One of the greatest leaders raised by Yūfīlās was Alaric I, the legendary king of the Visigoths. A devoted monotheist and follower of Arius, Alaric fought against Byzantine and Roman forces starting in 395 in search of a safe homeland for his people. In 410 AD, when he became the first commander in history to breach the gates of Rome, he shattered the myth of the “Eternal City’s” invincibility. Alaric’s aim was not barbaric pillaging, but to establish a secure order that would liberate Arian communities from Roman oppression.

After Alaric, the Visigothic Kingdom transformed into a powerful state centered in Toulouse. It reached its golden age during the reign of the Arian monotheist king, Theodoric I. His influence was so significant that modern literary critics find echoes of him in Tolkien’s character Theoden in The Lord of the Rings. Spain, Portugal, and southern France came under the umbrella of this kingdom.

However, this monotheistic order was shaken when Recarado I converted to Catholicism in 586 for political reasons. While the majority of the population remained Arian, the court’s turn toward the Trinity caused the kingdom to fracture from within. It was during these very years that a child was born on the Arabian Peninsula: the Prophet Muhammad ﷺ. With him, the banner of tawhid rose once more, quickly reaching North Africa, and then the former territories of the Visigoths.

This is why the entry of Tariq ibn Ziyad into Andalusia in 711 was not merely a military conquest. Many Arian Goths, weary of Catholic oppression, allied themselves with the Muslims; in many places, the city gates opened without a fight. The tawhid brought by the Muslims revived the suppressed essence of Arianism. From then on, Andalusia—with its Córdoba, Toledo, Seville, and Granada—would become one of the most brilliant civilizations in human history.

The Ostrogoths and Theoderic: The Arian King of Justice

Another great stage for tawhid in post-Roman Europe was the Ostrogothic Kingdom. By the end of the 5th century AD, this kingdom ruled over an immense territory covering parts of present-day Italy, Switzerland, Austria, Germany, France, and Spain. At its heart stood a great ruler devoted to the Arian monotheistic faith: Theoderic the Great.

In his book Ragnarok: The Fate of the Gods, Terry Unger writes:

“The famous great king Theoderic had provided his people with security and peace for fifty years. He was an Arian; yet his people knew him and loved him. His kingdom encompassed all of Italy, part of Germany, part of Gaul (France), and most of Spain. He also held influence over a large part of North Africa.”

Theoderic’s greatness lay not only in the sharpness of his sword, but also in his justice, his commitment to religious freedom, and the balance he established through a dual legal system. Arian Goths, Catholic Romans, and various tribes and sects lived under their own legal frameworks, and no community was persecuted merely because of its faith. Trade routes were repaired, urban order was restored, tax burdens were eased, and the weak and poor were cared for.

The mosaics in the Basilica of Sant’Apollinare Nuovo in Ravenna—whose faces were scraped off—stand as fossilized proof of how the Catholic Church sought to erase this Arian past. The figures walking between the columns were destroyed; only faint traces of hands, garments, and shadows remain. Like the Arian kings who were to be erased from history…

While the Church tried to erase Theoderic’s name and faith, the collective memory of the people glorified him. In Germanic and Scandinavian sagas, he appears as Dietrich von Bern—the embodiment of the ideal king who stood against tyranny. Although Dante tried to condemn him from a Catholic perspective by placing him in hell in The Divine Comedy, in popular lore, Theoderic remains a symbol of justice and courage.

The contradiction is made clear in the words of Jerome, the translator of the Bible into Latin:

“Most of the world is in astonishment. For people wonder how Theoderic, who brought peace to the people, could be an Arian.”

The Vandal Kingdom: The Silent Bridge of Monotheism in North Africa

During the same centuries, another Arian people emerged onto the historical stage: the Vandals. This Germanic tribe, descending from Northern Europe, embraced an Arian monotheistic creed—one that viewed Jesus as the servant and messenger of God—through the preaching of Wulfila. In the early 5th century, they crossed the Rhine, joined forces with the Alans, and reached the Iberian Peninsula in 409, settling in Hispania Baetica. The people began to call the region “Vandalusia,” a name that would later evolve into Andalusia.

It was during these years that the young Geiseric grew up witnessing the torture, burnings, and exile of Arian believers—atrocities that filled him with deep anger toward Rome. In 429, he crossed the Strait of Gibraltar with his army. When he arrived in North Africa, the people welcomed him not as an invader, but as a liberator from Roman oppression. This was because the vast majority of Christians in North Africa were already Arians.

When the Vandals besieged Hippo, one of the greatest figures in Catholicism, Saint Augustine, was in the city and died under siege—a twist of fate that brought one of Catholic theology’s most prominent names to his final breath in the shadow of Arian armies. The Vandals then conquered Carthage and built one of the largest naval fleets in the Mediterranean. In 455, Geiseric entered Rome, and the city remained under Vandal control for two weeks. Roman historians were fond of calling this the “Vandal sack,” but in reality, it was far less bloody than centuries of Roman conquests—it was a scene marked more by wounded imperial pride and seized spoils than by mass slaughter.

Centuries later, the Catholic world coined a new term to portray the Vandals as barbaric and destructive: “vandalism.” Rome’s own legacy of razing cities, slaughtering populations, and burning temples was conveniently forgotten, while the word was imposed upon a monotheistic Arian kingdom. It was one of the most insidious tricks of language in the history of political propaganda.

Still, history could not fully silence the voice of truth. The Cambridge Ancient History records the following observation:

“The people of North Africa welcomed the Vandals not as invaders, but as liberators. For the Vandals abolished Rome’s heavy taxes, ended the oppression of Catholic priests, and granted the people the freedom to live according to their own beliefs.”

In 468, the combined Roman–Byzantine fleet was burned to ashes off the coast of Cap Bon in Tunisia by Geiseric’s fire ships loaded with olive oil. Within hours, hundreds of ships were destroyed, and control of the Mediterranean passed to the Vandals. During their rule in North Africa, taxes were reduced, cities were rebuilt, trade and agriculture flourished, and Arian monotheism prevailed.

At the command of Emperor Justinian I, the Byzantine general Belisarius came to Africa with promises of “bringing justice.” Carthage opened its gates to him. But as soon as he seized power, the Roman order returned: Arian churches were shut down, clergy were exiled, heavy taxes were reimposed, and Catholic priests regained dominance. In 534, the Vandal Kingdom was destroyed—but the legacy of monotheism continued to live on in the hearts of the people.

As Professor Thomas R. Martin reminds us:

“We must not forget that the vast majority of the people in the Roman provinces of North Africa were Arian Christians. We should view the arrival of the Vandals not as an invasion, but as the natural continuation of the creed.”

Less than a century later, when Muslim armies reached North Africa, the people did not see Islam as a “foreign religion,” but as the return of a lost tawhid. Between the fall of the Vandal Kingdom and the rise of Islam in North Africa and Andalusia lies a hidden bridge—one that most history books ignore, but which the memory of the land has not forgotten.

The City of Tawhid: Istanbul

And now, as Pope Leo XIV bends over the waters of Nicaea to revive the memory of the council, the real question remains: Who will remind him of Arius and the Arians? Who will recount how the voice of tawhid, silenced 1,700 years ago, echoed through these lands for centuries?

Who today remembers the historical fault line indicated by the Prophet Muhammad (peace be upon him) in his letter to the Byzantine Emperor Heraclius, where he mentioned the “Arians”? Who still recalls the truth sensed in that letter—that the monotheistic current rising from within Christianity held the potential to unite with Islam’s call?

And let us not forget a perhaps lesser-known detail: the first inhabitants of Istanbul were the peoples of the Maghreb. Constantine, the founder of the city, brought the first population from Libya, Tunisia, Algeria, and Morocco. The ancient city of Constantine in present-day Algeria stands as the second center he established—virtually a “second Istanbul.” In the stones of this city circulates not only the mark of Rome but also the breath of tawhid that came from Africa.

Istanbul is a city of tawhid. Hagia Sophia, the Column of Constantine, the shadow of the city walls, the intertwined mosques and churches—all unite on the same horizon, where the traces of Arians that were meant to be erased meet the banner of unity once again raised by the Muslims.

In the end, it all comes down to this:
The Pope is coming to Nicaea, but Arius is still beneath the water…

To remember him is to honor the struggle for unity that still lives on in the memory of this land. To speak again of that silent name—waiting beneath the water, in the carved-out faces of mosaics, in the shadows of the stones—is not only a historical duty of knowledge, but also a moral duty in the name of truth.