This year marks 1700 years since the Council of Nicaea. Churches around the world will mark it with various festivities. Despite how it will invariably be presented, the Council was not actually a moment of great unity for the Church. Indeed, as a look at its proceedings will show, it more closely resembled Armando Iannucci’s film The Death of Stalin  than a great moment of ecumenical unity.

The council was called by the Emperor Constantine. Previously emperor only in the West of ancient Rome’s dominions, in 324 he had usurped his brother-in-law Licinius, the emperor in the East, and reunited the Roman Empire under his rule. He had also, in 312, converted to Christianity. Consequently, aligning the beliefs of the Christians who were resident in his new eastern lands was a priority for Constantine. It was easier said than done.

On one side was the Arian party lead by the two Eusebiuses: Eusebius of Nicomedia, a distant relation of the emperor, described as ‘an unscrupulous intriguer’; and his quieter, scholarly and more widely-admired sidekick, Eusebius of Caesarea. This pair of Eusebii were partisans for the Alexandrian deacon Arius. A smelly and ill-kempt oddball, Arius had become the poster boy for the idea of Christ as a created, inferior being to God the Father, rather than one with the Godhead.

On the other side, opposing this and asserting strongly the full divinity of Christ, was the confusingly monikered Bishop Alexander of Alexandria with his brilliant and precocious protégé Athanasius. They hated Arius and had already booted him out of Egypt and into Palestine.

The man who Constantine tasked with reconciling these two parties was Hoseus, the wily and elderly bishop of Cordoba. Hoseus had acted as the young Constantine’s factotum in the West and now came to the East to act as convener of the Council. Hoseus was nearly 70 by the time of the proceedings and had been elected to his see during the persecutions of Diocletian, having himself barely escaped martyrdom at the hands of Rome. Now, by contrast, he was the powerbroker for the entire empire, East and West.

Nicaea was not the opening salvo. Hoseus convened a warm-up council in Antioch at the start of the year. Most records are lost, but from that which remains, and that which happened afterwards, we can safely assume that it did not go well. The Bishop of Antioch selfishly chose to die just as proceedings began. His successor was a man called Eustathius, a bruiser from southern Turkey, who had already spent the first chunk of his career shaking the church in Aleppo into shape. He was renowned for his outbursts of polemic and as an anti-Arian partisan. He was hardly a conciliatory candidate and contributed to the collapse of the council.

Clearly, the theological crisis within Christianity was worse than the new regime had feared. As far as Hoseus was concerned, the Christians of the East were even madder than he had imagined. He decided to convene a council closer to the seat of imperial power, at Nicaea in modern-day Turkey. The emperor himself would be present to keep the recalcitrant bishops in line.

Immediately, the parties began their manoeuvres. Eusebius sought to contact as many eastern bishops as possible to persuade them that he would speak for them. Meanwhile, Alexander rushed to court, and there persuaded Hoseus to thrust the question of the nature of Christ to the very heart of the council, hoping by sleight of hand to settle the issue once and for all and leave his rivals out in the cold.

The council began with a series of exhortations to unity and good grace made by the emperor himself. To these the bishops gamely assented before almost immediately resorting to mudslinging. Bishops read out accusations and counter-accusations against colleagues. It is thought unlikely that these had anything to do with theology, as they had to be submitted in written form before the key theological question of the council had even been determined. As things did turn to theology, the situation worsened. Some bishops grew fed up of the endless discussion and took things into their own hands – it is probably a legend that St Nicholas, Bishop of Myra, went as far as to punch Arius in the face, but it probably captures the general mood.

Eusebius of Nicomedia, probably aware of the trap that had been laid for his party, ‘sent up a balloon’ to gauge the mood of the council and tried to begin the theological part of proceedings by setting out his own definition of the nature of Christ. This was promptly shot down. The Alexandrian party smelled blood and probably felt comfortable in allowing the weaker Eusebius  – he of Caesarea – to step forward and try a final roll of the dice for the party sympathetic to Arius.

Eusebius stepped forward and simply recited what he said his little church in Caesarea believed. His statement was filled with scriptural quotations, from the gospel of John and from the epistles of Paul. It also used a number of Arian formularies: specifically referring to Christ as ‘the first born of all creation’. Eusebius had been the victim of a concerted effort to smear his doctrine as heretical some months prior to the council. Doubtless the Alexandrian party were ready to complete the work of discrediting the Bishop of Caeserea. It was not, however, to be. Just as Eusebius finished his speech, a member of the council stood up to speak. It was the emperor. Constantine remarked that he thought it an excellent statement of faith, lacking only one thing: an explicit statement that Christ was of ‘the same essence as the Father’.

To this all sides readily assented. None dared dispute with the emperor directly. Inevitably, however, the real detail was thrashed out in later stages. The Alexandrian party inserted a variety of extra clauses and, perhaps most importantly, secured a series of anathemas, curses and excommunications of those who taught things contrary to it. This included Arius. One by one the bishops agreed.

Some made sure to cover their backs, however. Eusebius of Caesarea made sure to send back a letter to his Arius-sympathising church, justifying his position and with the caveat that ‘rumours travel faster than accurate information’.

Even Eusebius of Nicomedia eventually agreed to sign up to the creed, but, in one last act of solidarity with his weird friend Arius, refused to endorse the anathemas. That was good enough for Constantine: order had been restored. And it was order above all that Constantine craved. The council concluded a few months later, having also set the method for calculating Easter. Proceedings ended with a banquet, at which heavily armed men watched over the bishops as they ate, in order to stop any further fisticuffs.

This order would not reign for long. The psychoses of Constantine’s family soon picked apart the fragile peace he had created: not least his wife and son having an affair which resulted in both their executions. In the end, the Arian party managed to use its sway in the imperial household to pick apart the settlement. Specifically, Eusebius returned to the fray, baptising the emperor on his deathbed – Constantine having declined to be baptised before so as to ensure that his manifold sins didn’t catch up with him. Eusebius became a major factotum during the reign of Constantine’s vain, overly trusting and easily flattered son, Constantius. First on his agenda was revenge: he manoeuvred to have Eustathius sacked from his bishopric and sent into exile, summoned Hoseus endlessly to tribunals in an attempt to do the same, and persecuted Athanasius, who had succeeded his mentor Alexander as Bishop of Alexandria.

In the end though, it was a non-Arian formulation of the creed that triumphed – adapted at the Council of Constantinople in 381 and, most critically, at the Council of Chalcedon in 451. It is still used in Christian worship across the world, week by week. For all the later additions, it is known as the Nicene Creed.

What, you might ask, is the relevance of all this? Why should we moderns care about a series of queeny hissy fits thrown by bishops in Asia Minor 1700 years ago?

Well, for all its dysfunction, Nicaea actually set the tone for the concept of conciliar discussion which continues to this day. It was by no means guaranteed that Constantinian Christianity would proceed with a conciliar model. Nicaea was the first ecumenical council proper since the direct apostles of Christ had met in Jerusalem in the years after his death and resurrection. That Nicaea was considered a success set the model in motion to continue. This didn’t only have ecclesiastical consequences: in setting the model used by the Church, it also set that used by nation states. The Munich Security Conference that recently descended into Nicene levels of disagreement is closer to its fourth-century progenitor in more ways than one.

This leads us to the next reason why Nicaea matters. It set in motion the dance between Church and State which continues, with various degrees of harmony, to this day. While it was the Edict of Thessalonica in 380 that formally established Christianity as a ‘state religion’, it was at Nicaea, and with Constantine’s intervention, that the process of formal engagement between Church and State began. It is one that is still under way.

In terms of what was decided upon, Nicaea was also crucial in the development of Christology. And a High Christology – the concept of God and Man held together in the person of Jesus Christ – has become essential to western concepts of personhood. Why human lives matter, how they matter, is entirely tied up with what was decided at Nicaea.

Finally, perhaps most important of all, it was at Nicaea that the concept of the credal statement as an instrument of unity and of differentiation received its formal baptism. We live in a more credal age than we have done for some time. What people subscribe to by way of a statement of faith – political, economic, religious or just social – is of crucial importance in a western society where the question of ‘what is it we believe?’ is more up for grabs than ever. It might be 1700 years since those glorious temper tantrums, and acts of Machiavellian guile, but the spirit of Nicaea is much closer than we might think.