Politics and the world of faith in late antiquity - 1700 years of the Council of Nicaea

In 325 AD, hundreds of bishops from all over the Roman Empire gathered in the city of Nicaea, now İznik in Turkey. They had been invited by Emperor Constantine - for a simple but explosive reason: a fierce dispute had broken out in the young Christian church, threatening the unity of the faithful and thus also the stability of the empire. It was about nothing less than the question of who Jesus Christ actually was - and how he related to God. The First Council of Nicaea was an attempt to resolve this dispute. It was the first major meeting of its kind and a turning point: Christianity took a major step towards becoming a state religion - a development that would fundamentally change not only the Church, but also the Roman Empire.

2025 marks the 1700th anniversary of this event. A good reason to commemorate it - the Roman town of Carnuntum is doing so with a new special exhibition in the Carnuntinum Museum. Only a few years earlier, in the year 308, Carnuntum itself was the scene of the so-called Imperial Conference - and thus of an important political decision. What was decided back then in the metropolis on the Danube prepared the ground for Constantine's later rise - and therefore also for the Council of Nicaea.

In the 3rd century AD, the Roman Empire came under increasing pressure. Emperors came and went, internal power struggles and external threats put pressure on the once mighty empire. In order to stabilize the empire, Emperor Diocletian introduced a new system of government: the so-called tetrarchy - a quadripartite rule with two highest-ranking emperors (Augusti) and two deputies (Caesares). The aim was to better distribute tasks and better protect the borders - especially in provinces such as Pannonia, where Carnuntum was located.

However, this system did not last long. After Diocletian's resignation, power struggles broke out again. In 308, three emperors - Diocletian, Galerius and Maximian - therefore met in Carnuntum to discuss the future of the empire at the so-called Imperial Conference. Although they were unable to find a lasting solution, the meeting was an important step: it opened the way for a young man named Constantine, who would rise to become the most powerful man in the empire in the years to come.

A a late roman crested helmet - © W. Artner 

After many years of fighting, Constantine prevailed over his rivals. In 324, he became the sole ruler of the Roman Empire. From the outset, he pursued a new policy: instead of continuing to fight Christianity - as his predecessors had done - he protected it. He had already ended the persecution of Christians with the Edict of Toleration in Milan in 313. But now he went one step further: he wanted to make Christianity the unifying force in the empire.

However, there was no unity within the church itself. The priest Arius from Alexandria in particular caused a stir with his teachings. He was of the opinion that Jesus Christ was not equal to God the Father, but subordinate to him. Other church representatives saw things differently. The dispute came to a head - and threatened to split Christianity as a whole.

Lance tip with ribbon inlays - © W. Artner 

To end this conflict, Emperor Constantine convened the Council of Nicaea just one year after his final accession to power. He invited bishops from all over the empire - from Spain to Syria, around 300 of whom attended. They debated for weeks. In the end, they agreed on a common creed: Jesus Christ was “of the same essence” as God the Father - in other words, true God and true man at the same time. The teachings of Arius were condemned as heresy.

This was a historic moment. For the first time, a council bindingly established what the church believed - and it was the emperor who had made it possible and supported it politically. Christianity thus became a matter of state - and the emperor became the supreme patron of the church.

What does all this have to do with Carnuntum? A lot. Because this is where the emperors met 17 years before the Council to save the political order. Without the imperial conference of 308, Constantine's rise would hardly have been possible. The succession of Diocletian was decided in Carnuntum - with consequences for the entire empire. Even though Carnuntum gradually lost importance after the rise of Constantine, the city remained an important place of late antique politics in the 4th century. The construction of the Pagan Gate - today's landmark of Carnuntum and the surrounding region - around the middle of the 4th century shows that people here continued to see themselves as part of the great Roman history. With its monumental design, it is reminiscent of Constantine's buildings in Rome and Constantinople.

1700 years of the Council of Nicaea - this is far more than just a commemoration of a theological meeting. It commemorates a time when the Roman Empire reinvented itself: politically, religiously and socially. Christianity was brought out of persecution and made the guiding principle of the empire. Emperors became God's representatives - and places such as Carnuntum became the sites of historical milestones. In the anniversary year 2025, it is therefore worth looking not only to Nicaea, but also to Carnuntum - to a place where politics and faith opened a new chapter in Roman history. For it was here, on the Danube border, that a chapter began that has shaped Europe to this day.

The special exhibition “1700 Years of the Council of Nicaea: Faith and Politics in Late Antiquity”, which opened on June 6, provides an insight into the turbulent times of early Christianity and offers finds that have never been presented to the public before and represent outstanding masterpieces of Roman craftsmanship.