The normative importance of the Council of Nicaea in the Orthodox tradition cannot be overestimated. A landmark event in cementing the authority of the Council of Nicaea was the Council of Constantinople (381). In the fifth century, Cyril of Alexandria was singularly concerned about promoting the Nicene Creed and making the interpretation of its second article a focal point in the Christological controversy. The Council of Ephesus (431) formulated the principle of unchangeability of the Nicene faith. The Council of Chalcedon (451) reaffirmed this principle and, building upon the precedent of the Council of Constantinople, advanced a hermeneutic of continuity with the Council of Nicaea. In the sixth century, the Nicene faith passed into the Byzantine liturgy in the form of the Constantinopolitan Creed rather than the original Nicene Creed. In addition, the role of the Council of Nicaea was safeguarded in the Orthodox Church’s liturgical memory through the feast days dedicated to different aspects of the council. The council also left a mark in hagiography and iconography. During the Filioque Controversy, the Nicene legacy, especially the Constantinopolitan Creed without the Filioque clause, was turned into a marker of a Byzantine Christian as opposed to Latin Christian identity.

In 525 Dionysius Exiguus compiled his 95-year continuation of the Alexandrian Paschal table, which eventually scheduled the celebration of Pasch for the entire western Church. He also stated that the Council of Nicaea had authorized the 19-year Alexandrian Paschal cycle and that this had been maintained by subsequent Alexandrian bishops. These statements were challenged by Jan in 1718, and since then the question of Nicaean authority has been disputed. However, while the Synoptic Gospels agree that the Crucifixion took place on the day after the Jewish Passover, John’s Gospel places it on the day of the Passover and hence on the fourteenth day of the spring moon. Thus the Evangelistic accounts of Jesus’s Crucifixion conflict chronologically. Consequently, the Asian churches chose to emphasize the Crucifixion by celebrating Pasch on the fourteenth day of the moon, while other churches emphasized the Resurrection by celebrating it on Sunday. At Nicaea Constantine sought to resolve this conflict, and contemporaneous accounts agree that the Council decreed that Pasch be celebrated only on Sunday, and forbade celebration on the fourteenth day. This chapter concludes that the origin of the Alexandrian Paschal table lies rather with bishop Theophilus in the last decades of the fourth century.

The main acts of Nicaea were gradually reversed over the years 327-60. Constantine honored its name and canons throughout his life, but recalled Arius from exile, leaned on church leaders to restore him to communion, and sidelined Arius’s opponents. Constantius II flouted Nicaea’s canons and officially replaced its creed. Nonetheless, Nicaea’s pronouncements on the Son’s relationship to the ousia of the Father, including the term homoousios, which had been a response to Eusebius of Nicomedia’s Letter to Paulinus of Tyre, continued to be debated throughout this period in a succession of mutually allusive theological works. These include Eusebius of Caesarea’s Letter to his Church, Eustathius of Antioch’s Against the Arian Madness, Asterius the Sophist’s Defence of Eusebius of Nicomedia, Marcellus of Ancyra’s Against Asterius, Eusebius’s Against Marcellus and On Ecclesiastical Theology, Acacius of Caesarea’s Against Marcellus, Marcellus’ Letter to Julius of Rome, Athanasius’s Orations Against the Arians, the Profession of Faith of Sirmium 351, and Athanasius’s On the Decrees of Nicaea. The last of these, together with his formidable political skills, established the Nicene Creed against all the odds as the only formula which was able to command widespread support among bishops across the empire after the death of Constantius.

This chapter narrates the emergence of the pro-Nicene alliance by arguing that it was a consensus-building movement. It begins by tracing the history of other consensus-building movements in the fractured theological landscape of the years 325-61 in order to demonstrate their development of various consensus-building tactics, which were ultimately used unsuccessfully. The impetus for the pro-Nicene alliance itself was dissatisfaction with, or the failure of, these previous efforts. Pro-Nicenes adopted four tactics of previous consensus-building efforts and deployed them successfully: (1) defining itself as the center between extreme positions, (2) promoting a minimalist creed that nonetheless ruled out extremes to be avoided, (3) acknowledging that the meaning of a creed was not self-evident and producing supplementary material to insure its correct interpretation, and (4) securing imperial patronage. The chapter then turns to shifts in thinking which occurred in the early 360s and made consensus between former opponents possible, taking Athanasius of Alexandria and Basil of Caesarea as paradigmatic examples of these shifts. The chapter concludes by narrating the consolidation and ascendency of the pro-Nicene alliance in the late 370s and early 380s.

This chapter discusses the evidence for the existence of creeds before Nicaea and the purpose for which they might have been employed. The rival accounts of the origin of the Nicene formula are compared, together with the variants in the wording and the different accounts of its origin. The biblical texts that lie behind each verse of the creed are examined, and Beatrice’s argument for a pagan origin of the term homoousios is weighed against other theories. The anathemas require particular study, since the anathema on the term ktiston (“created”) is not preserved in all sources, but is crucial to the argumentation of Athanasius, who claims that it has the authority of Eusebius. The chapter then asks how the Nicene Creed was regarded after the end of the council, and whether subsequent creedal formulations were meant to reinforce or supersede it, and how it attained the form that is now regularly employed in churches.

It was not until the aftermath of the Council of Ariminum (359) and its Constantinopolitan confirmation (360), which officially professed a Homoian creed, that a pro-Nicene reaction took shape and galvanized the West. In the decades that followed a series of Latin bishops wrote apologetic-like discourses, defending the Nicene faith (against the authority of Ariminum) by providing renewed interpretations of the Nicene Creed and the relations of the Father, the Son, and the Holy Spirit.  Following in the tracks of Hilary of Poitiers and Marius Victorinus, a small handful of writers such Gregory of Elvira, Ambrose of Milan, Zeno of Verona, and Augustine gradually carved out a pro-Nicene doctrine of the Trinity and adjoining biblical hermeneutics that had completely rid itself of Photinian elements. By the Council of Aquileia (381), neo-Nicenes formed a hegemony, but one which did not dominate the theological and political landscape until the mid-380s.

This chapter examines the physical surroundings and circumstances of the first ecumenical council at Nicaea. The first part summarizes what we know of the city of Nicaea, what it looked like in the early fourth century, and if it had the necessary infrastructure to host a large gathering. The chapter also considers why the council was moved to Nicaea from Ancyra as well as why Nicaea was favored over the nearby imperial capital of Nicomedia. The next part focusses on the location, character, and size of the venue of the council, the palace of Nicaea. After a more general discussion of the complex, the author attempts to shed light on the physical form of the hall in which the bishops gathered by reviewing the evidence for audience halls known from other imperial and private palaces. Both the possibility of the council taking place in a large basilica-like setting and an alternative of the bishops convening inside a rotunda are considered. Finally, there is a brief comparison of the setting of the Nicaean council and contemporary Christian meeting places.

The Council of Nicaea was a landmark event, yet uncertainty surrounds almost every aspect of the council and its proceedings. No Acts survive, the signatory lists are incomplete, and the organization of the council’s meetings and the identities and motivations of those who participated remain controversial. Rather than propose another hypothetical reconstruction, the aim of this chapter is to reconsider the different interpretations made possible by our limited evidence and the particular questions that have divided scholarly opinion. Who attended the council? Who took the leading roles in the council’s deliberations? And who proposed and supported the crucial decisions, such as the inclusion of the contested term homoousios into the Nicene Creed? Not only are such questions essential to understanding the council and its legacy, but our search for answers offers the opportunity to look beyond the emperor Constantine and the most famous episcopal protagonists, and consider the significance of Nicaea for some of the less prominent figures who contributed to the drama. While their voices are difficult to hear, these more humble individuals had their own parts to play and shared the contemporary awe at a spectacle that symbolized the changing status of Christianity within the fourth-century Roman empire.

During the formative period of disputation over the theology of Arius, the emperor Licinius ruled over the eastern Roman provinces. The emperor Constantine was directly involved in the doctrinal controversy only after his victory over Licinius in 324. But Constantine’s engagement in imperial politics had already shaped his thinking about theology. In imperial successions sons were sometimes promoted but also sometimes overlooked. Emperors introduced a new five-year cycle for calculating taxes and often held annual consulships. Emperors identified with deities such as Jupiter and Hercules. At the Council of Nicaea, Constantine was hence ready to debate with bishops over the theology of Father and Son, the annual date of Easter, and the simultaneous divinity and humanity of Jesus Christ. One bishop who attended the council was Eusebius of Caesarea, whose panegyric equated the emperor with the Son of God. Constantine himself strengthened the association by funding churches in honor of Jesus’s nativity and resurrection in the Holy Land and by publicizing a story about his own vision of a cross in the sky. The Council of Nicaea had been a crucible for the formation of both a theology of God and a political philosophy of a Christian emperor.

How the long-standing genre of historical manuscripts show how writers worked with a broad and important sense of their place within a tradition.