Did Constantine create the Catholic Church?

It’s a common question and a persistent myth in some circles. The idea that Emperor Constantine founded the Catholic Church or “took over” early Christianity has captured imaginations, but the historical facts tell a different story. In reality, the Catholic Church’s roots go back to Jesus Christ and the apostles in the first century – long before Constantine’s time (see Eusebius, Ecclesiastical History; Pelikan, The Christian Tradition; Chadwick, The Early Church). This article will explore the history of the early Church and show why Constantine did not create the Catholic Church. We’ll debunk the myth with solid historical evidence, covering how the early Christian church developed, what Constantine actually did (and didn’t do), and how later events prove the Church was never simply a creation of one emperor. Read on to discover the real history of the early Church and Constantine’s role – it might surprise you!

History of the Early Church Before Constantine

To understand why Constantine didn’t found the Catholic Church, we first need to look at the history of the early Church before his era. Christianity began in the 1st century A.D., arising from the ministry of Jesus Christ and His apostles in the Middle East. From those earliest days, a community of believers took shape – a community that would later be called the “Catholic” Church (meaning “universal” church). In fact, historical records show that Christians were referring to the Church as “Catholic” as early as A.D. 110. Saint Ignatius of Antioch, writing in his Letter to the Smyrnaeans 8.2, said: “Wherever Jesus Christ is, there is the Catholic Church.” This demonstrates that a well-structured Christian Church existed and was known as the Catholic (universal) Church long before Constantine.

Early Christianity spread throughout the Roman Empire despite periods of harsh persecution. For example, Christians faced imperial persecutions under emperors like Nero in the 1st century and Diocletian in the late 3rd century. These early Christians formed a network of local churches led by bishops, and they held to core beliefs about Jesus, the scriptures, and sacraments. Importantly, the Catholic Church traces its history back to Jesus Christ and the Apostles themselves, not to any later political figure (cf. Denzinger). In other words, the Church was already nearly 300 years old by Constantine’s time.

It’s true that by the early 300s the Church was still a persecuted minority in the Roman Empire. But it had a solid identity and structure (bishops, councils, scriptures, traditions) developed over generations. Christian writers before Constantine – Church Fathers like St. Irenaeus in the 2nd century and Tertullian in the early 3rd – discussed a unified church across the world, i.e., a “universal” (catholic) church. So, when Constantine comes on the scene in the 4th century, he encounters an existing Catholic Church – one with roots going back to the very foundation of Christianity. He did not invent it. As Henry Chadwick and Jaroslav Pelikan both affirm, the Church’s apostolic structure predates imperial sponsorship by centuries.

Constantine’s Impact on Christianity – What Did He Really Do?

If Constantine didn’t create the Catholic Church, what was his role in Christian history? Constantine the Great (reigned A.D. 306–337) was the first Roman emperor to convert to Christianity. His reign marks a turning point for the Church, but not because he founded it – rather, because he ended the persecutions and favored the Church’s growth.

In A.D. 313 Constantine (along with co-Emperor Licinius) issued the famous Edict of Milan, which legalized Christianity throughout the empire. This Edict of Milan granted Christians the freedom to worship openly and ended the era of state-sponsored persecution. However – and this is crucial – the Edict of Milan did not make Christianity the official state religion of Rome. That only happened under Theodosius I in 380 AD.

Constantine’s own mother, St. Helena, played a pivotal role in his journey toward faith. While some historical sources suggest Constantine introduced her to Christianity, the majority of tradition and patristic sources indicate that Helena was already a devout Christian before her son’s conversion. Her piety and devotion likely influenced Constantine’s openness to the Christian faith. Helena is also credited with the discovery of the True Cross during her pilgrimage to the Holy Land, further underscoring her prominent place in Christian tradition.

Constantine himself did embrace Christianity and used imperial resources to benefit the Church. He built great churches (basilicas) in Rome and Jerusalem, promoted Christians to high offices, and bestowed favors on clergy. He even founded a new capital city, Constantinople, which he intended as a “New Rome” with a Christian character. But again, none of this amounted to creating a new church – he was supporting an existing Church.

One major event Constantine is famous for is the Council of Nicaea in A.D. 325. This was the first ecumenical (worldwide) council of Christian bishops, called by Constantine to resolve the Arian heresy. According to ecclesiastical tradition, 318 bishops were present at the council—a number considered symbolic and frequently cited by Church Fathers like St. Athanasius. The Council affirmed Christ’s full divinity and issued the Nicene Creed, a document still professed today across Catholic, Orthodox, and many Protestant churches. Importantly, this Council was not an innovation, but a continuation of the apostolic practice of gathering to settle doctrinal disputes – just as we see in Acts 15, when the apostles convened in Jerusalem to discern the matter of Gentile observance of Mosaic Law.

The Council’s decrees were made by the bishops, not imposed by Constantine, who served as convener and supporter, not theologian or legislator. This affirms the Church’s internal authority to define doctrine, grounded in apostolic tradition, not its dependence on the emperor.

Christianity as State Religion – A Later Development

A key clarification: Constantine did not make Christianity the official religion of the Roman Empire. While he provided unprecedented support and favor to the Church, the Edict of Milan only legalized Christianity, granting religious freedom throughout the empire. Pagan practices continued under Constantine, and he retained the title of Pontifex Maximus, the chief priest of the Roman state religion.

It was only decades later, in 380 AD, under the reign of Emperor Theodosius I, that Christianity became the official state religion through the Edict of Thessalonica. This decree declared Nicene Christianity the sole authorized religion of the empire. Theodosius later outlawed pagan worship entirely, signaling a significant shift from Constantine’s earlier pluralistic approach.

This distinction is critical. Those who claim Constantine “created” the Catholic Church often conflate his patronage with institutional control. But the historical record shows that the Church’s autonomy and apostolic authority were already well established.

Church Independence: The Case of Ambrose and Theodosius

One of the clearest examples of the Church’s independence from imperial power came after Constantine’s time. In 390 AD, after the massacre of thousands of civilians in Thessalonica, Bishop Ambrose of Milan publicly rebuked Emperor Theodosius I and barred him from receiving the Eucharist until he performed public penance. Ambrose’s stance, supported by ecclesiastical tradition and recorded in multiple sources, reflects the Church’s moral authority over even the most powerful rulers.

Theodosius eventually submitted, laid aside his imperial garments, and sought absolution in the Church. This event, immortalized in Christian memory and art (notably in Van Dyck’s painting), illustrates that the Church was not subservient to the emperor. Instead, it exercised independent authority grounded in conscience and tradition.

After Constantine: A Mixed Imperial Relationship

Following Constantine’s death, the relationship between the Church and the empire was anything but uniform. His son, Constantius II, supported Arianism and exiled Nicene bishops, including St. Athanasius. Later, Emperor Julian the Apostate rejected Christianity altogether, attempted to revive paganism, and reversed many of Constantine’s policies.

These examples further dismantle the idea of a seamless union or “takeover” of Christianity by the empire. The Church continued to face opposition, adapt, and uphold its teachings even when imperial favor was withdrawn. Such resilience points to an institution whose foundations lie beyond political influence.

Conclusion: The Church Was Not Constantine’s Invention

So, did Constantine create the Catholic Church? No. The Church had already existed for nearly three centuries, with a structure, doctrine, and community rooted in Christ and the apostles. Constantine’s reign marked a turning point for the Church’s public presence but did not alter its core identity.

He did not invent its teachings, compose its creeds, or appoint its bishops. The Council of Nicaea, widely accepted even among many Protestant denominations, stands as a testament to the Church’s capacity to govern itself through apostolic tradition. His mother, St. Helena, stands as a powerful witness to Christian faith before imperial favor.

From Ignatius of Antioch’s use of the term “Catholic Church” to the Nicene bishops’ theological clarity, the historical evidence consistently points to a Church born of the Gospel, not the government.

If this article helped clarify the truth about Constantine and the early Church, share it with someone who might be holding on to the myth. Let's help more people discover the deep, rich, and authentic roots of the Church that has endured beyond emperors, regimes, and centuries.

References

1. Eusebius of Caesarea – Ecclesiastical History. Translated by G.A. Williamson. Penguin Classics, 1989.

2. Jaroslav Pelikan – The Christian Tradition: A History of the Development of Doctrine, Vol. 1: The Emergence of the Catholic Tradition (100–600). University of Chicago Press, 1971.

3. Henry Chadwick – The Early Church. Penguin Books, Revised Edition, 1993.

4. Denzinger, Heinrich – Compendium of Creeds, Definitions, and Declarations on Matters of Faith and Morals. Edited by Peter Hünermann, Ignatius Press, 2012.

5. Ignatius of Antioch – Letter to the Smyrnaeans, 8.2. In: The Apostolic Fathers, translated by Bart D. Ehrman, Harvard University Press, 2003.

6. Athanasius of Alexandria – Defense of the Nicene Definition (especially for the reference to 318 bishops).

7. Edict of Milan (313 AD) – As recorded by Lactantius in De Mortibus Persecutorum and Eusebius in Vita Constantini.

8. Edict of Thessalonica (380 AD) – Issued by Emperor Theodosius I; see Codex Theodosianus XVI.1.2.

9. Saint Ambrose – Letters and writings related to the excommunication of Theodosius, e.g., Letter 51.

10. Historical commentary on Emperor Julian (“the Apostate”) – As found in Ammianus Marcellinus and Sozomen, Ecclesiastical History.

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Emperor Theodosius I kneels in penitence before Saint Ambrose inside a grand basilica, having removed his imperial garments as a sign of humility. The bishop stands firm, granting absolution only after the emperor enacts justice.