This chapter traces the fortunes of our modern understanding of ‘belief’ which is deeply informed by its original uses in a religious context. It begins with an account of faith/belief (Greek: pistis) in early Christianity, showing how the primary meanings of the term related to trust rather than intellectual assent. In the medieval period, this social component of faith/belief was formalised in the conception of ‘implicit faith’, which enabled lay believers to affirm abstruse theological doctrines without the requirement of a full intellectual comprehension of what was being affirmed. While it is possible to speak of the propositional content of belief during this period, the identity of the faithful was established more by liturgical practice than assent to doctrinal propositions.

This chapter examines the ways in which creeds have been collected in late sntiquity and in modern scholarship. Radde-Gallwitz first sketches the history of modern anthologies of creeds and argues that they have led to a conflation of distinct types of creeds, particularly in their portrait of a genealogical relation between creeds without anathemas and creeds containing anathemas. He argues that late-antique sources, by contrast, emphasise anathemas in their presentation of creeds. He examines sources such as canon collections and Athanasius’ De synodis and provides a new account of the afterlife of the anathema appended to the original Nicene Creed.

Church councils formed an integral part of medieval canon law, indeed one might say its backbone. Nicaea I in 325 will be our starting point, for, although this council belongs to the early Church, its influence upon medieval canon law was profound. It was first in the list of councils that came to be regarded as ecumenical, that is, as a council of the whole Church. Although ecumenical councils form the main focus of this chapter, attention will also be given to local councils, which played important roles in canonical development.

The introduction to this volume begins with a reflection on the impact of Dan Brown’s novel, The Da Vinci Code, especially for its presentation of the Council of Nicaea as a conspiratorial moment in the history of Christianity. It then offers a sweeping examination of how various contemporary Christian traditions and denominations have received the Council of Nicaea and its creed and how they understand historical figures such as Arius and Constantine. As we near the 1,700-year anniversary of the first “ecumenical” council, the chapters in this volume will revisit old debates and discussions, ask new questions, and offer different perspectives on the people, context, and consequences related to the Council of Nicaea.

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.